Collection Of LCD TV Repair Cases
Here we'll be providing a collection of LCD TV repair cases, gathered from a good reliable source. We've seen some of these cases in our repair lab and have proven to be very helpful.
PART 1
Samsung LE32R73BD: No picture and no OSD menu. Backlight ok.
Model/s: Samsung LE32R73BD LCD TV
Symptom: No picture and no OSD menu. Backlight ok.
Cure/Solutions: Reflow LVDS socket on screen driver PCB and mainboard PCB.
SAMSUNG LE32R74BD: TV dead. Pulsating noise from PSU and LED light flashes.
Model/s: Samsung LE32R74BD LCD TV
Symptom: TV dead. Pulsating noise from PSU and LED light flashes.
Cure/Solutions: Check shottky diode DM854 (MBRF1545CT) in PSU for short circuit.
BUSH LCD32TV005HD: After TV on few seconds, then the TV off again.
Model/s: BUSH LCD32TV005HD APH000 Chassis BEKO LM LCD TV
Symptom: Picture appears for a few seconds after switch on, after that the TV switches off again.
Cure/Solutions: Check C2042 and C2044 (both 680uf/35v) in PSU for capacity loss.
BUSH LCD32TV005HD: No Picture and no back light. Front controls react and remote control does not.
Model/s: BUSH LCD32TV005HD APH000 Chassis BEKO LM LCD TV
Symptom: No Picture and no backlight. The front controls was working but remote control does not
Cure/Solutions: Replace IR receiver (short circuit).
JVC LT32DX7B: No functions after lightning strike
Model/s: JVC LT32DX7B LCD TV
Symptom: No functions after lightning strike.
Cure/Solutions: The primary voltage 300v is present. But secondary voltage output was only 21 volt. Replace standby transformer T9201.
Sharp LC32P55E: Red LED appears for a seconds, relay clicks then dead.
Model/s: Sharp LC32P55E LCD TV
Symptom: Red LED appears for a seconds, relay clicks then dead.
Cure/Solutions: The resistor R751 blown. Replaced IC704 & R751.
Sharp LC32P55E: Dead after start-up. Bang-noise head before
Model/s: Sharp LC32P55E LCD TV
Symptom: Dead after start-up. Bang-noise head before.
Cure/Solutions: Replace R751 (0.1R/2W), IC704, D762, D725 and C725 (470pF/3K) in PSU.
Philips Chassis BJ3.0E LA: Switches off for a second or two intermittently
Model/s: Philips Chassis BJ3.0E LA LCD TV
Symptom: Switches off for a second or two intermittently. Relay clicks and standby LED remains green. Switches off intermittently with green LED on, no sound or no picture.
Cure/Solutions: Please check the 27MHz KDS quartz crystal (SSB, item 1H00). If all yellow marked crystals bearing with a "5E", "5J" or "5K" batch number direct replaced it. Also replaced all the silver marked crystals bearing with a "6D" batch number.
LG 37LE2R: No start-up
Model/s: LG 37LE2R Chassis LP61A LCD TV
Symptom: No start-up.
Cure/Solutions: Replace SMD regulator TL431 (U130) in PSU.
LG 27LC2R: No Backlight
Model/s: LG 27LC2R Chassis LP61A LCD TV
Symptom: No backlight
Cure/Solutions: Check the SMD fuse F1 on inverter board for open circuit.
Samsung LE27T51B: Dark frame with color stripes
Model/s: Samsung LE27T51B LCD TV
Symptom: Dark frame with color stripes.
Cure/Solutions: It looks like the unstable voltage problem. Check and replace UP4 (L1117DG) on T-CON board.
LG 32LE2RZJ: Remote control no functions at all
Model/s: LG 32LE2RZJ Chassis LP61A LCD TV
Symptom: Remote control doesnt function at all.
Cure/Solutions: Replace SMD capacitor at output of IR receiver.
ACER AL2671W: Dead
Model/s: ACER AL2671W LCD TV
Symptom: Dead.
Cure/Solutions: Replace power supply IC (TNY264PN) and resistor R60 (10R/0.33W, NFR type).
ACER AL2671W: No start-up. LED is orange
Model/s: ACER AL2671W LCD TV
Symptom: No start-up. LED is orange.
Cure/Solutions: When C380 unsuccessfully replaced. Standby PSU functions and standby 5v present. The voltage appears at pin PSON in the PSU after switch on but PSU does not start. Actually they are three 330K SMD resistors in series in the PSU which supply voltage for DLA001. Check if resistors are high resistive.
Bush IDLCD26TV05HD: No backlight and no picture. Sound ok and can be intermittently
Model/s: Bush IDLCD26TV05HD Chassis L9 (Beko) LCD TV
Symptom: No backlight and no picture. Sound ok and can be intermittently.
Cure/Solutions: Replace C512, C513 (both 1000uF/35v) and C519 (220uF/35v) in PSU. Also a 1000uf/16v capacitor on the signals board on the far right-hand side, near the top.
SONY KDL40U2000: No start-up, red LED flashes 3 times
Model/s: SONY KDL40U2000 with SE1 Chassis LCD TV
Symptom: No start-up, red LED flashes 3 times.
Cure/Solutions: TV has slow start-up before this symptom occurred. When check standby 5v ok and PSU is heat sensitive. Check and replace the C6055 (47uf/25v) in G2 supply it will solve the problem.
BUSH LCD32TV022HD: Intermittently no start-up or dead after a few hours
Model/s: BUSH LCD32TV022HD with 17MB15 Chassis LCD TV
Symptom: Intermittently no start-up or dead after a few hours.
Cure/Solutions: The PSU replaced and EEPROM IC resoldered, but on help. Try to resolder IC220 (SDA5550) and IC224 on main board the TV back to normal.
EVESHAM ALQEM37SX: No start-up, the TV screen lights up, then switches back to standby mode
Model/s: EVESHAM ALQEM37SX with 17MB15 Chassis LCD TV
Symptom: No start-up, the TV screen lights up, then switches back to standby mode.
Cure/Solutions: Please check or direct replace the C877 and C878 on PSU board for open circuits. Sometime these caps will check good, but would breaks down under load.
Grundig GULENAR32HDIP: Stuck in standby mode, LED light is blue color
Model/s: Grundig GULENAR32HDIP with Chassis L9 LCD TV
Symptom: Stuck in standby mode, LED light is blue color.
Cure/Solutions: The blue LED always stays on, even when appliance is on standby mode. Capacitor C931 (1000uF) replaced but appliance is still dead with 12v and 24v ok. Check and replace diode D300 on the right-hand side, on middle-top of the main board.
Samsung LN40A650_A750_LN46A750: Unit tries to start with melody but cycles off and back on
Model/s: Samsung LN40A650A1FXZA,LN46A650A1FXZA,LN40A750R1FXZC,LN46A 750R1FXZA,LN40A750R1FXZA LCD TV
Symptom: Unit tries to start with melody but cycles off and back on
Cure/Solutions: If the unit tries to turn on and makes the startup melody but then immediately shuts off and starts again, unplug the LVDS cable and apply power again. If the set stays on, replace the T-Con board.
Samsung LNT4665FX/XAA lost brightness when you replaced MAIN PCB
Model/s: Samsung LNT4665FX/XAA LCD TV
Symptom: LNT4665FX/XAA lost brightness when you replaced MAIN PCB
Cure/Solutions: Because MAIN PCB BN94-01199E is designed to work with both models LNT4665FX/XAA and LNT4661FX/XAA when you replaced the board is possible to lose the brightness. Go in SERVICE MODE and turn value LVDS BYTE from 8 to 10.
Samsung LNS4051: Dead Backlight Flashes On Then Off
Model/s: Samsung LNS4051DX/XAA LCD TV
Symptom: DEAD BACKLIGHT FLASHES ON THEN OFF
Cure/Solutions: UNIT WOULD FLASH ON THEN OFF AND AUDIO WOULD WORK. YOU COULD SEE VIDEO WITH A FLASHLIGHT. SOMETIMES UNIT WOULD STAY ON AND RUN IF YOU CYCLED ON AND OFF MANY TIMES. FOUND BAD SOLDER CONNECTION ON IP BOARD TI801 ON PRIMARY SIDE. RESOLDERED AND CORRECTED PROBLEM.
Samsung most model: Flickering on the screen intermittently
Model/s: Samsung
LN32B360C5DXZA,LN32B530P7FXZA,LN32B460B2DXZA,LN32B 540P8DXZA,LN32B550K1FXZA,LN37B530P7FXZA,
LN37B550K1FXZA,LN40B550K1FXZA,LN40B530P7FXZA,LN40B 530P7NXZA,LN40B530P7FXZC,LN40B540P8FXZA,
LN46B530P7NXZA,LN46B530P7FXZA,LN46B550K1FXZA,LN46B 540P8FXZA.
Symptom: Flickering on the screen intermittently
When the unit is connected via HDMI to a Scientific Atlanta cable set top box set in by pass mode for resolutions 480p and 720p a flickering will occur.
Cure/Solutions: Change the cable box to a fixed resolution. OR Have the customer install the latest TV firmware which can be located on samsung.com.
Samsung most model: Unit cycles on/off during startup
Model/s: Samsung LN46A550P3FXZA,LN46A650A1FXZA,LN46A530P1FXZA,LN46A 750R1FXZA,LN46A860S2FXZA,LN46A950D1FXZA,
LN46A540P2FXZA,LN46A850S1FXZA,LN46A630M1FXZA,LN46A 580P6FXZA,LN52A530P1FXZA,LN52A750R1FXZA,
LN52A650A1FXZA,LN52A550P3FXZA,LN52A630M1FXZA,LN52A 860S2FXZA,LN52A850S1FXZA,LN52A540P2FXZA,
LN40A530P1FXZA,LN40A450C1DXZA,LN40A330J1DXZA,LN40A 550P3FXZA,LN40A650A1FXZA,LN40A630M1FXZA,
LN40A540P2FXZA LCD TV.
Symptom: Unit cycles on/off during startup
Cure/Solutions: If the unit tries to turn on but begins to cycle on and off before any video is displayed and all of the SMPS voltages are good, disconnect the LVDS cable at the T-Con board. If the set starts and the backlights come on, replace the T-Con board. If the set does not start, disconnect the LVDS cable at the main board. If the set starts, replace the LVDS cable. If the set still does not startup, replace the main board.
Samsung LNT3253: After a few minutes when TV warms-up picture becomes distorted
Model/s: Samsung LNT3253HX/XAA LCD TV.
Symptom: After a few minutes when TV warms-up picture becomes distorted
Cure/Solutions: 10-15 minutes after you turned on the unit panel warms-up and picture becomes distorted. If you just push the TV's frame picture becomes even more distorted. On the back of the panel the CONTROL ASIC area is very hot. Replace the panel to fix the problem.
Re: Collection Of LCD TV Repair Cases
PART 2
Samsung: LN32A450_LN32A330: Video will intermittently turn mostly white
Model/s: Samsung LN32A450C1DXZA,LN32A450C1HXZA,LN32A450C3HXZA,LN32A 330J1DXZA,LN32A330J1NXZA LCD TV
Symptom: Video will intermittently turn mostly white
White display with a faint image of OSD (On Screen Display) and video in the background. Video will intermittently turn mostly white with the OSD barely visible in the background. Even a black image or when the panel should not be showing any video, it is white. I found that one of the sub-boards inside the panel, the boards that the ribbon cable from the T-Con connect to, are not seated properly and the larger SMD capacitors on the board are intermittently making contact with the metal frame of the set, effectively creating a short to ground.
This is one of the panels that are mounted upside down, so the stand mounts just below and behind the panel frame. Any slight pressure from the stand can cause the frame to make contact. In many cases, the TV can be slightly flexed to make this issue occur.
You may see besides a T-Con ribbon cable, that the sub-board is not seated properly, and is in fact bowing towards the outer frame.
Pulling the frame out slightly, you can see one of the SMD capacitors that can make connection with the frame.
Cure/Solutions: Adding felt to the affected area will solve the issue.
Samsung most model: Firmware Blinking in Red at the Top of the Screen
Model/s: Samsung LN32B360C5DXZA,LN32B530P7FXZA,LN32B650T1FXZA,LN32B 460B2DXZA,LN32B540P8DXZA,LN32B550K1FXZA,
LN32B640R3FXZA,LN32B457C6HXZA,LN32B450C4HXZA,LN37B 457C6HXZA,LN37B530P7FXZA,LN37B650T1FXZA,
LN37B550K1FXZA,LN40B457C6HXZA,LN40B550K1HXZA,LN40B 500P3FXZA,LN40B550K1FXZA,LN40B650T1FXZA,
LN40B530P7FXZA,LN40B530P7NXZA,LN40B750U1FXZA,LN40B 540P8FXZA,LN40B610A5FXZA,LN40B630N1FXZA,
LN40B640R3FXZA,LN46B650T1FXZA,LN46B530P7NXZA,LN46B 530P7FXZA,LN46B550K1FXZA,LN46B610A5FXZA,
LN46B540P8FXZA,LN46B630N1FXZA,LN46B640R3FXZA,LN46B 750U1FXZA,LN52B550K1HXZA,LN52B610A5FXZA,
LN52B550K1FXZA,LN52B540P8FXZA,LN52B530P7FXZA,LN52B 630N1FXZA,LN52B750U1FXZA,LN55B640R3FXZA,
LN55B650T1FXZA LCD TV.
Symptom: Firmware blinking in Red at the top of the screen.
Cure/Solutions: Problem - After changing the main board, I'm now stuck with the firmware text info blinking in RED print at the top of the screen.
Solution : The unit is stuck in aging mode. To exit, simply hit the menu button on the TV itself.
Samsung LNT4065_LNT5265: With Signal-Blue Screen and Flashing White Short Horizontal Lines
Model/s: LNT4065FX/XAA,LNT4665FX/XAA,LNT5265FX/XAA,LNT4061FX/XAA,LNT4661FX/XAA
Symptom: Blue screen without signal, with signal -blue screen with flashing white short horizontal lines
Cure/Solutions: Refit or replace LVDS cable, check if the cable not strangled by the metal cover and loosen up the screws of the cover.
Samsung LNT3242_3232 : Wont Power On
Model/s: Samsung LNT3242HX/XAA,LNT3232HX/XAA LCD TV
Symptom: Wont power on
Cure/Solutions: TV would not come on. Removed the back and as soon as we did the set came on.
Found glue all on the cables to the smps. Cleaned glue off and cleaned the terminals. Set operates normally.
ACER AL2671W: No start-up. LED is orange
Model: Acer AL2671W LCD TV
Symptom: No start-up. LED is orange.
Cure/Solution: Check C380 (100uf.16v) under heatsink, next to U42 and U61 on signal PCB for capacity loss.
Sony KDL32U2000: No Picture
Model: Sony KDL32U2000 Chassis SE1 LCD TV
Symptom: No Picture
Cure/Solution: Check SMD fuse CP101P on LVDS board. The LVDS board is behind the BDT board.
SONY KDL32S2010E: Switches to standby for a short while, then back again
Model: SONY KDL32S2010E Chassis WAX2 LCD TV
Symptom: Switches to standby for a short while, then back again
Cure/Solution: Replace standby push button on user control, has contact resistance.
Philips 32PF3320/10: "F" is displayed on screen
Model: Philips 32PF3320/10 Chassis LC4.5 EAA LCD TV
Symptom: "F" is displayed on screen
Cure/Solution: TV is in factory mode. To quit the factory mode, press both "VOLUME" "-" keys and "PROGRAM" "-" for 5 seconds simultaneously.
LG 32LC56: Picture divided into several parts. Distorted picture
Model: LG 32LC56 LCD TV
Symptom: Picture divided into several parts. Distorted picture
Cure/Solution: Replace T-CON board (Part Number: 218394).
LG 32LC56ZC: No start-up. Standby LED flashes from red to green
Model: LG 32LC56ZC LCD TV
Symptom: No start-up. Standby LED flashes from red to green
Cure/Solution: Replace C202, C206, C217 and C218 (2200uf/10v all), and C226 (470uf/25v).
GOODMANS GTV26WLCD: Shuts down and LED blinks
Model: GOODMANS GTV26WLCD LCD TV
Symptom: Shuts down and LED blinks
Cure/Solution: Replace C877 and C878 (both 15nf/630V) near heatsink, at top left corner of PSU
BUSH LCD26TV006HDX: No display. Flashing standby light
Model: BUSH LCD26TV006HDX LCD TV
Symptom: No display. Flashing standby light.
Cure/Solution: The capacitor C315 (1000uF/25v) is supplied higher rated, and is a little bigger so use longer leads don't fit close to board. Be careful when soldering you don't accidentally remove the tiny surface mount resistors on back of board.
Samsung LN32A330: The TV takes longer to power on than normal
Model/s: Samsung LN32A330J1DXZA,LN32A330J1NXZA LCD TV
Symptom: The TV takes longer to power on than normal
The TV takes longer to power on than normal. You may hear several clicks while the TV attempts to power on.
Cause: The electrolytic in the capacitors on the power supply board over time will dry out causing the power supply to shut down during its initial power on cycle.
Cure/Solutions: Refer to the capacitor cross reference guide below for the list of the capacitors that should be replaced.
Samsung: Unit tries to start with melody but cycles off and back on
Model/s: Samsung LN40A650A1FXZA,LN46A650A1FXZA,LN40A750R1FXZC,LN46A 750R1FXZA,LN40A750R1FXZA LCD TV
Symptom: Unit tries to start with melody but cycles off and back on
Cure/Solutions: If the unit tries to turn on and makes the startup melody but then immediately shuts off and starts again, unplug the LVDS cable and apply power again. If the set stays on, replace the T-Con board.
Samsung: Will not turn on, cycles on and off with startup melody, no backlights
Model/s: Samsung LN52A650A1FXZA,LN40A650A1FXZA,LN46A650A1FXZA,LN52A 650A1FXZC,LN46A650A1FXZC LCD TV
Symptom: Will not turn on, cycles on and off with startup melody, no backlights
Cure/Solutions: If the set will try to turn on and the startup melody sounds but no backlight appears and the set cycles off and on every 5 to 10 seconds, unplug the LVDS cable from the T-Con/FRC board. If the set then runs and the backlights come on and stay on, replace the defective T-Con/FRC board.
Samsung LNS4692: No video TV, has backlight and audio. TV will not come on
Model/s: Samsung LNS4692DX/XAA LCD TV
Symptom: No video TV, has backlight and audio. TV will not come on.
Cure/Solutions: Found pico fuse open at cp1 on the T-CON pcb short cp1 TV comes on runs fine. Replace the T-CON pcb.
Samsung: Standby light is on, flashes once briefly then unit attempts to turn on
Model/s: Samsung LN32A330J1DXZA,LN32A450C1DXZA,LN32A550P3FXZA,LN32A 540P2DXZA,LN32A330J1NXZA,LN32A450C1HXZA,LN32A450C3 HXZA, LN32A300J1DXZA LCD TV
Symptom: Standby light is on, flashes once briefly then unit attempts to turn on
Cure/Solutions: If the unit will not turn on, but the red standby LED is on and flashes once quickly when the power button is pressed on the remote or the TV, the 2200uf 10v filter capacitor on the SMPS has failed. This capacitor is located in the upper right side of the power supply close to the cable that connects the main board. Visual inspection will normally show that it has a swollen top. Replace capacitor and inspect the others in the filter stage to restore operation.
Collection Of LCD TV Repair Cases
PART 3
Samsung: Unit cycles on and off several times before starting
Model/s: LNT4069FX/XAA,LNT4066FX/XAA,LNT4669FX/XAA,LNT4071FX/XAA,LNT4671FX/XAA,LNT5271FX/XAA,LNT4065FX/XAA,LNT4665FX/XAA,LNT5265FX/XAA,LNT4061FX/XAA,LNT4661FX/XAA
Symptom: Unit cycles on and off several times before starting
Cure/Solutions: If the unit will cycle on and off several times before turning on and then playing fine, check the power supply carefully for filter capacitors with bulged tops. Replace the capacitors or power supply to correct the issue.
Samsung: Auto-shutdown on 2008 LCD TV’s
Model/s: Samsung LN32A330J1DXZA,LN32A450C1DXZA,LN32A650A1FXZA,LN32A 550P3FXZA,LN32A540P2DXZA,LN32A330J1NXZA,LN32A300J1 DXZA, LN40A530P1FXZA, LN40A450C1DXZA, LN40A750R1FXZA, LN40A330J1DXZA, LN40A550P3FXZA, LN40A540P2FXZA, LN40A500T1FXZA, LN46A530P1FXZA, LN46A860S2FXZA, LN46A750R1FXZA, LN46A550P3FXZA, LN46A650A1FXZA, LN46A950D1FXZA, LN46A540P2FXZA, LN46A500T1FXZA, LN46A850S1FXZA, LN46A630M1FXZA, LN46A850S1FXZX, LN46A580P6FXZA, LN52A530P1FXZA, LN52A750R1FXZA, LN52A650A1FXZA, LN52A550P3FXZA, LN52A630M1FXZA, LN52A860S2FXZA, LN52A850S1FXZA, LN52A540P2FXZA, LN52A580P6FXZA.
Symptom: Auto-shutdown on 2008 LCD TV’s.
Cure/Solutions: Upon inspections of 2008 LCD TV's we have found that the LVDS (ribbon cable) can cause an auto shut down. Even if the LVDS cable doesn’t look defective try changing it anyway and retest the TV. It is a good practice to carry a few extra LVDS cables in your van for such testing circumstances.
Samsung: Unit tries to start with melody but cycles off and back on
Model/s: Samsung LN40A650A1FXZA,LN46A650A1FXZA,LN40A750R1FXZC,LN46A 750R1FXZA,LN40A750R1FXZA LCD TV
Symptom: Unit tries to start with melody but cycles off and back on.
Cure/Solutions: If the unit tries to turn on and makes the startup melody but then immediately shuts off and starts again, unplug the LVDS cable and apply power again. If the set stays on, replace the T-Con board.
Samsung LNS2651 & LNT3242: Picture is lost, sound OK after MAIN PCB was replaced
Model/s: Samsung LNT3242HX/XAA, LNS2651DX/XAA LCD TV
Symptom: Picture is lost, sound OK after MAIN PCB was replaced
Cure/Solutions: If after replacing MAIN PCB and made all correct setups in "OPTION BYTE" you get the symptoms:
- lost picture after 5-10 min. but sound OK, picture comes back if you restart the LCD but just to be lost again after the same interval or
- Picture is lost intermittently every 10-20 sec. and comes back itself, again sound OK.
You may not have to come back with another Main PCB, this may be corrected just by moving the connection between inverter and SMPS on the SMPS board. If it was on A-CNM803 move it to S-CNM802 or vice versa from S-CNM802 to A-CNM803 on the SMPS board, see picture. If this is not working then use a new MAIN PCB.
This may be applied to other LCD models too.
Samsung LNS4051: Clicking repeatedly TV will not turn on
Model/s: Samsung LNS4051DX/XAA LCD TV
Symptom: Clicking repeatedly TV will not turn on
Cure/Solutions: Found 2 electrolytic 100uf at 16v capacitors on the 5v line C115 and C123 bad. Or replace the power supply.
Samsung: Backlight Failure Testing
Model/s: Samsung LN32B360C5DXZA,LN32B530P7FXZA,LN32B650T1FXZA,LN32B 460B2DXZA,LN32B540P8DXZA,LN32B550K1FXZA,LN32B640R3 FXZA, LN32B457C6HXZA, LN32B450C4HXZA, LN32B540P8DUZA, LN32B450C3HXZA, LN32B460B2DUZA, LN32B360C5DUZA, LN32B550K1FUZA, LN32B530P7FUZA, LN32B450C3HUZA, LN40B530P7FUZA, LN40B550K1FUZA, LN40B457C6HXZA, LN40B550K1HXZA, LN40B610A5FUZA, LN40B640R3FUZA, LN40B650T1FUZA, LN40B630N1FUZA, LN40B540P8FUZA, LN40B500P3FXZA, LN40B550K1FXZA, LN40B650T1FXZA, LN40B530P7FXZA, LN40B530P7NXZA, LN40B750U1FXZA, LN40B540P8FXZA, LN40B630N1FXZA, LN40B640R3FXZA, LN52B550K1HXZA, LN52B610A5FXZA, LN52B550K1FXZA, LN52B540P8FXZA, LN52B530P7FXZA, LN52B630N1FXZA, LN52B750U1FXZA LCD TVs.
Symptom: Backlight Failure Testing
Cure/Solutions: Backlight failures can be partial or full failure Check the backlight supply voltage (refer to service manual) If supply voltage is present, use a flashlight behind the television and shine a light through the panel. If the video is working you will see it.
Samsung LNS4041: Unit Continually Cycling On and Off
Model/s: Samsung LNS4041DX/XAA LCD TV
Symptom: Unit Continually Cycling On and Off. Set turns on and off in a continuous cycle. Plays the melody each time.
Cure/Solutions: First, check the power supply voltages, if missing, replace the power pcb. Next unplug the lvds cable. If the set continues to cycle, replace the main pcb. If the cycling stops, replace the lcd panel. Part numbers are version dependent, so be sure to check the set's version.
Samsung LNT4671 & LNT5271: TV is cycling, the red led blinking and the relay is cycling
Model/s: Samsung LNT5271FX/XAA,LNT4671FX/XAA LCD TV
Symptom: TV is cycling, the red led blinking and the relay is cycling sometime TV will come on.
Cure/Solutions: TV is cycling, the red led blinking and the relay is cycling sometime TV will come on. The Main board replaced, did not fix. This unit was a Refurb, found cable from the main board to the side AV jack was reversed, is not labeled as to direction of use. This cable if reversed will be hot to the touch. Found by removing and replugging and changing direction of cable TV worked. This was tried on both model numbers with the same result.
Hitachi 37LD6600: No sound or intermittent sound
Model/s: Hitachi 37LD6600, 37LD6600A LCD TV
Symptom: No sound or intermittent sound
Cause: Pins of headphone socket touching the chassis.
Cure/Solutions: Trim the pins of the Headphone socket.
Hitachi 37LD6600: MECHANICAL NOISE FROM SCREEN ONLY IN CINEMA MODE
Model/s: Hitachi 37LD6600, 37LD6600A LCD TV.
Symptom: MECHANICAL NOISE FROM SCREEN ONLY IN CINEMA MODE
Cause: High back light setting on Cinema mode.
Backlight settings are different for each mode :
DYNAMIC: 00
NATURAL: 50
CINEMA : 100
Cure/Solutions: Reduce backlight settings in Cinema mode from 100 to 59 as follows.
Enter Service Mode with the remote control,
PRESS MENU
4725 OR 1267 OR 1461 (there are 3 different software versions, only one code will work)
Service Menu will appear, Select PIC ADJUST and enter with VOL+
A second service menu will appear, the bottom adjustment in the menu is Back Light setting and will be set to 100.
From the Mode Heading select CINEMA mode.
Select Back Light and reduce the setting to 59.
To memorize and exit Service Mode press Standby.
Hitachi 32LD7200: Distorted Sound/Audio
Model/s: Hitachi 32LD7200 LCD TV
Symptom: Distorted Sound/Audio
Sound is distorted when the set is first switched on. After a while the fault clears and the set works normally.
Cure/Solutions: Replace Joint PWB. p/n: TP01336.
Hitachi 32LD7200: MECHNICAL NOISE FROM SCREEN IN DYNAMIC MODE
Model/s: Hitachi 32LD7200 LCD TV
Symptom: MECHNICAL NOISE FROM SCREEN IN DYNAMIC MODE
Cause: Low back light setting on Dynamic mode.
Backlight settings are different for each mode :
DYNAMIC : 12
NATURAL : 15
CINEMA : 10
Cure/Solutions: Increase backlight settings in Dynamic mode from 12 to 20
If similar noise problem occurs on other modes, adjust backlight levels to the position in which noise becomes minimum..
ADJUSTMENT
Backlight level can be adjusted in USER menu only.
Select Menu ----- Picture ----- Backlight ------ and adjust as necessary.
Hitachi 32LD6600: No picture, but sound ok
Model/s: Hitachi 32LD6600_A_B_C LCD T V
Symptom: No picture, but sound ok.
Cause: Dry joints on components S627 and S629 near connector PL308 on the main board.
Cure/Solutions: Resolder components S627 and S629 and also check other components for dry joints near the connector.
Hitachi 32LD6200: Unit does not switch on or fails to power on
Model/s: Hitachi 32LD6200_A_B_C LCD TV
Symptom: Unit does not switch on or fails to power on
Unit does not work, standby LED not lighting.
Cause: Working of Pixelworks controller IC21 depends on ambient temperature.
If the IC is heated externally the unit starts to work normally.
Cure/Solutions: Replace Ferrite bead L500 and L501 with a jumper wire.
Hitachi 32LD6200: Set fails to power on/switch on
Model/s: Hitachi 32LD6200_A_B_C LCD TV
Symptom: Set fails to power on/switch on.
If MB11-6 Main board is used instead of the original Main board MB11-2 the unit won't switch on.
Unit switches off immediately and a clicking noise comes from the Power Regulator Board.
Countermeasure:
Replace the LVDS cable (p/n: VS30041693) and add a 47uF(p/n: VS30000396, CAP EL47UF16V) electrolytic capacitor to Power Regulation Board .
Hitachi: Picture Display Problem
Model/s: Hitachi 32LD6200_A_B_C, 32LD6600_A_B_C LCD TV
Symptom: Picture Display Problem
Cause: Various picture problems can be caused by poor connection of the LVDS cable on connector PL103 on the Main board.
Cure/Solutions: Remove LVDS cable from connector PL103 and reinsert carefully.
Make sure both end of the LVDS cable are inserted properly between PL103 and the display panel.
Sharp: The Sharp LCD TV still under protection mode?
Model/s: SHARP LCD TV Repair tips
Symptom: The Sharp LCD TV still under protection mode?
The Sharp LCD TV always have the protection mode come out. Normally, the repairer will first check the inverter board, after that power board/PSU, if still can't get any result, then they will check the signal board or mainboard. Even you change the inverter or PSU board, the lcd TV still under protection mode. Sometime, the lcd TV has been fixed by the repairer, but they don't know the TV still remember the protection mode inside the memory. So, now you need to know how to clear this protection error inside the lcd TV memory.
Cure/Solutions: Press & hold the CHANNEL DOWN & VOLUME UP buttons, then ON the LCD TV. The LCD TV Protection Error has been clear & solve the TV problem.
Hyundai: Slow start-up
Model/s: Hyundai Imagequest HQL260WR LCD TV
Symptom: Slow start-up
Cure/Solutions: Replace capacitor C109, C110 and C111 (all 1000uf/35v). Also check SMD resistor R56 and R57(both 22K) for dry joints.
Hyundai: Shuts down after a few minutes
Model/s: Hyundai Imagequest HQL260WR LCD TV
Symptom: Shuts down after a few minutes
Three 1000uf electronic capacitors in PSU replaced unsuccessfully.
Cure/Solutions: Change optocoupler IC PC102-2.
Collection Of LCD TV Repair Cases
PART 4
LG: No start-up. Standby LED flashes from red to green
Model/s: LG 32LC56ZC LCD TV
Symptom: No start-up. Standby LED flashes from red to green
Cure/Solutions: Check or replace C202, C206, C217, C218 (all 2200uF/10v) and C226 (470uF/25v).
LG: Picture divided into several parts. Distorted picture
Model/s: LG 32LC56 LCD TV
Symptom: Picture divided into several parts. Distorted picture
Cure/Solutions: Replace T-CON (Part Number: 218394).
LG: Stuck in standby
Model/s: LG 32LC56ZC LCD TV
Symptom: Stuck in standby
Cure/Solutions: Check & change C204. If pcb board discolored around R208 then replace PSU.
LG: "No Signal" displayed
Model/s: LG 32LC45 LCD TV
Symptom: "No Signal" displayed. No sound and no picture. Backlight and OSD menu ok. LED is green color light.
Cure/Solutions: Try to update firmware if not then replace main signal board.
LG: No Power
Model/s: LG 47LF66 LCD TV
Symptom: No power
Cure/Solutions: Change C202, C206 and C217 (all 2200uf/10v) on IP board (Power Supply Inverter Board).
LG: No Power
Model/s: LG 37LF66 LCD TV
Symptom: No power
U500 (ICE3B1565J) short circuit and fusible resistor FB501 (2.2R) open circuit.
Cure/Solutions: Check safety resistor for open circuit. Replace D501 (UF4007), 3.6v zener diode ZD502 (1N5227) and C508 (33uF/50v).
LG: Negative picture and no sound
Model/s: LG 47LY95 Chassis LD75A LCD TV
Symptom: Negative picture and no sound.
Voltage low at pin 7 of connector P202.
Cure/Solutions: Check Q202 (AP72T02GH), U203 (APU3037M), Q203 (AP60T03GH) and connector P202 in
PSU. Also check or replace C221, C222, C223 and C232.
LOGIK: No sound or picture. The front controls light up & relay clicks.
Model/s: Logik LCXW32HDI LCD TV
Symptom: No sound or picture. The front controls light up & relay clicks.
Cure/Solutions: Check or replace R65 (2M) in U3 PSU for open circuit.
Panasonic: Enter Service Mode.
Model/s: Panasonic TX-32LED7FM Chassis GLP22M LCD TV
Symptom: Enter Service Mode.
Cure/Solutions: 1. Press F button to access volume setting.
2. Press V- button on set until volume reaches minimum.
3. While still holding V- button press 0 button three times on remote control.
4. Press 1 and 2 buttons to scroll through the menu.
5. Press 3 and 4 buttons to select an adjustment.
Panasonic: Enter Service Mode.
Model/s: Panasonic TX-32LED7FM Chassis GLP22M LCD TV
Symptom: Enter Service Mode.
Cure/Solutions: 1. Press F button to access volume setting.
2. Press V- button on set until volume reaches minimum.
3. While still holding V- button press 0 button three times on remote control.
4. Press 1 and 2 buttons to scroll through the menu.
5. Press 3 and 4 buttons to select an adjustment.
Philips: Picture jitter if contrast function is used.
Model/s: Philips 23PF9966/37 LCD TV
Symptom: Picture jitter if contrast function is used.
Cure/Solutions: Replace transistor 7563 on Scaler board.
Philips: No sound
Model/s: Philips 23MW9010/37 LCD TV
Symptom: No sound
Cure/Solutions: Defective sound output IC7731 (AN7522).
Philips: Stuck in standby
Model/s: Philips 42PF7621/D10 LCD TV
Symptom: Stuck in standby. Switches to protection mode. Green LED flashes.
Cure/Solutions: Replace capacitors 2540 and 2544 (both 10nF). Change to both with 220nF.
Philips: High pitched noise coming from LCD supply
Model/s: Philips 42PF7621/D10 LCD TV
Symptom: High pitched noise coming from LCD supply
Cure/Solutions: Check or replace 5025, 5026 and 5027 at LCD supply and glue them if necessary.
Philips: Switches off for a second or two intermittently.
Model/s: Philips Chassis BJ3.0E_LA LCD TV
Symptom: Switches off for a second or two intermittently.
Relay clicks and standby LED remains green. Switches off intermittently with green LED on, no sound or picture.
Cure/Solutions: Check 27MHz KDS quartz crystal (SSB, item 1H00). Replace all yellow marked crystals (made in China) bearing a "5E", "5J" or "5K" batch number. Also replace all silver marked crystals (made in Taiwan) bearing a "6D" batch number. Note: Replace crystals with order code 242254301397.
Polaroid: No Start-up
Model/s: Polaroid FLM3232 LCD TV
Symptom: No startup.
Cure/Solutions: Replace Z9 zener diode with NTEPN4990 in the PSU.
SONY: Stuck in standby. Standby LED is green.
Model/s: Sony KDL32U2000 Chassis SE1 LCD TV
Symptom: Stuck in standby. Standby LED is green.
Red LED flashes 3 times. No remote control or front panel functions.
Cure/Solutions: Check or replace D301 zener diode (can be use a 5v zener diode) for short circuit.
SONY: Error codes 4
Model/s: SONY KDL40U2000 LCD TV
Symptom: Error codes 4
LED turns green, flashes 4 times then goes green again and flashes 4 times again. Fuse (500mA) on inverter panel open circuit.
Cure/Solutions: Replace the fuse on inverter board.
SONY: No start-up. Red LED flashes 3 times.
Model/s: SONY KDL40U2000 LCD TV
Symptom: No start-up. Red LED flashes 3 times.
Slow start-up before this symptom occurred. The standby 5v ok. PSU heat sensitive.
Cure/Solutions: Check C6055 (47uf/25v) in G2 supply.
Toshiba: Dead
Model/s: Toshiba 32WLT58 LCD TV
Symptom: Dead
Cure/Solutions: Check F870 (2A), Q860 (STRZ4479) and D866. If F801 open circuit, then check the voltage regulator Q820 for short circuit, R831 (4.7R/5W) and D825 (MTZJ33A).
Viewsonic: Picture flickers and is brighter on the right, than on the left
Model/s: Viewsonic N3260W VS114361M LCD TV
Symptom: Picture flickers and is brighter on the right, than on the left.
Cure/Solutions: Replace four electrolytic capacitors (2x 820uF and 2x 1000uF) in upper left PSU.
Viewsonic: No startup
Model/s: Viewsonic N3260W VS114361M LCD TV
Symptom: No startup
Cure/Solutions: Check capacitors (with ESR Capacitor tester), Q7 and SMD resistor R65 (5.1R) in primary side of PSU. This TV set using the FSP228-3F01 PSU.
Westinghouse: Blue screen. No sound, no picture and no OSD
Model/s: Westinghouse LTV40W1HDC LCD TV
Symptom: Blue screen. No sound, no picture and no OSD.
Cure/Solutions: Replace circuit protector fuse on T-CON board.
VIZIO: Green distortion in picture.
Model/s: Vizio VO42LFHDTV10A LCD TV
Symptom: Green distortion in picture.
Cure/Solutions: If PSU secondary side voltages ok. Check & clean contacts of ribbon cables coming from control board.
Wharfedale: Starts-up, backlight came after that switches off immediately.
Model/s: Wharfedale LCD3210AF Chassis 17MB116 LCD TV
Symptom: Starts-up, backlight came after that switches off immediately.
Runs ok when inverter board is externally supplied with 24v.
Cure/Solutions: Replace C877 and C878 (15nf/630v) between heatsink of switching transistor and larger transformer on the primary side of the PSU.
Collection Of LCD TV Repair Cases
PART 5
Hisense: Dead with a Bang Noise
Model/s: Hisense LCD4204EU LCD TV
Symptom: Dead with a Bang Noise
Cure/Solutions: Replace chopper drive STRX6769, RE038 (10R) and RE032 (150R) in primary PSU.
Goodmans: Dark picture. OSD bounces
Model/s: GOODMANS GTV32W22HD AVZOOO Chassis LM
Symptom: Dark picture. OSD bounces
Cure/Solutions: Replace C2042 and C2044 (680uf) in PSU.
Dell W2600: Erratic functions
Model/s: Dell W2600 LCD TV
Symptom: Erratic functions.
Sometime the TV locks-up problem, shuts down, no start-up and no remote control or front panel functions too.
Cure/Solutions: Resolder or reflow system ROM IC1234 and all regulator ICs on the mainboard.
DELL W2600: Display locks after 10 minutes
Model/s: Dell W2600 LCD TV
Symptom: Locks after 10 minutes
Cure/Solutions: Change regulator IC (LM1117 DT-2.5) on mainboard.
DELL W2600: No start-up after warm-up
Model/s: Dell W2600 LCD TV
Symptom: No start-up after warm-up
Cure/Solutions: Replace capacitor (10uf/50v) on small board mounted to power supply next to mainboard power connector.
Acer: No function on user control and remote control
Model/s: Acer AT3201W LCD TV
Symptom: No function on user control and remote control
When SCART module removed, remote control reaction ok.
Cure/Solutions: Replace electrolytic capacitors C348 and C350 (both 220uF/16v) on mainboard.
BUSH: No Backlight
Model/s: Bush IDLCD26TV05HD Chassis L9 LCD TV
Symptom: No Backlight
They are no 24v to the inverter board after a while. Sensitive to power supply tapping.
Cure/Solutions: Check & replace SMD 27v zener diode (red with yellow bands). Note: There are no reference numbers on any of the SMD components. The diode is located in primary side of the 24v chopper transformer supply, near pin5-8 of the SMD IC (UC3843A). (This PSU board is GDP002 ZR1910R NETZTEIL SPS 180W 24/5 12/5 PFC 2PIN(LISH)).
Hitachi: Intermittent Color or no color
Model/s: Hitachi 28LD5200E LCD TV
Symptom: Intermittent Color or no color
- Color drops out after the unit has been running for two to three hours.
Cure/Solutions: Resolder capacitor C510 and other components in its vicinity.
Hitachi: Poor image quality or polarization of image
Model/s: Hitachi 26LD6600 & 26LD6600A_B_C_D, 32LD8A10, 37LD6600, 37LD6600A & 37LD8500, 37LD8550, 37LD8600, 37LD8700C, 37LD8700CA, 37LD8700U, 37LD8700UA, 37LD8A20, 37LD8D10, 37LD8D20E, 37LD8D20U LCD TV
Symptom: Poor image quality or polarization of image
This phenomenon may be very intermittent and only displayed after a number of hours/days on soak
Cause: The glue on the LDVS cable heats up over time and the properties change and creating a contact problem within the cable and the PCB. This causes permanent or intermittent picture problems
Cure/Solutions: Remove the LDVS cable and clean the connections at the LCD control panel and replace the LVDS cable.
Hitachi: SOCKET CHANGE ON POWER BOARD 17PW15-9
Model/s: Hitachi 26LD6600 & 26LD6600A_B_C_D LCD TV
Tip: SOCKET CHANGE ON POWER BOARD 17PW15-9
Change: On the new version of Power Board 17PW15-9, socket PL805 has been changed to a 13 pin. On the earlier version of the power board socket PL805 is 12 pin.
When new Power Board with 13 pin ( PL805 socket ) is fitted to a set, the connector lead from socket PL805 must be changed .
Hitachi: CHANGE OF POWER SUPPLY FROM TYPE 17PW15-8 & 17PW15-9 TO 17PW20
Model/s: Hitachi 26LD6600 & 26LD6600A_B_C_D, 32LD8A10 LCD TV
Tip: CHANGE OF POWER SUPPLY FROM TYPE 17PW15-8 & 17PW15-9 TO 17PW20
The original power supply, version 17PW15-8 & 17PW15-9 has now been changed to the later version 17PW20
When fitting the new power supply, it may also be necessary to replace two cables with a new type as described below.
There is one new part number to replace all. This new part number will supply a kit that includes the power supply and the necessary new cable which you should use if required.
Remove the following connecting leads used with Power board 17PW15-8
1.Remove cable from Power board connector PL806 going to Mainboards MB15E-5 or MB15E-7 connector PL902.
2.Remove cable from Power board connector PL805 going to Mainboards MB15E-5 or MB15E-7 connector PL900 .
Replace the two cables with the new cable type:
Order New cable part number VS30049856
CHANGES:
Insert new cable:
1. On the Power Board Connect 12 pin connector of the new cable to PL805
2. On the Main Board: Connect the 7 pin connector of the new cable to PL902 and 12 pin connector to PL900.
Hitachi: FITTING NEW MAIN BOARD TYPE MB15E-7
Model/s: Hitachi 26LD6600 & 26LD6600A_B_C_D, 32LD8A10, 37LD6600, 37LD6600A, 37LD8600, 37LD8700C, 37LD8700U LCD TVs.
Tip: FITTING NEW MAIN BOARD TYPE MB15E-7
When new Main board type MB15E-7 is replaced instead of Main board type MB15E-5 the following changes have to be made.
REMOVE PARTS:
1. Remove and discard cable between Audio board (AMP05) connector PL709 and Main board connector PL1001.
2. Remove and discard cable between Audio board (AMP05) connector PL704 to main board connector PL903
CHANGES:
Order New cable part number VS30051586
Insert new cable:
On the main PCB Connect 6 pin connector of the new cable to PL1004.
On the Audio PCB you must first Check the version of Audio pcb fitted to the TV.
For Audio PCB version AMP05: Connect the 5 pin connector of the new cable to PL709 and 2 pin connector to PL704
For Audio PCB Version AMP03 : Connect the 5 pin connector of the new cable to PL709. As PL704 does not exist on this version the 2 pin connector must be removed and the cable then soldered to legs of D700 and D701.
New Chassis Version MB15E-7 changed in production as table below
Model Part Number Serial Number (From ~)
32LD8600A VS20286080 V61101471 ~
32LD8A10A VS20286080 V61101681 ~
Samsung: DEAD BACKLIGHT FLASHES ON THEN OFF
Model/s: Samsung LNS4051DX/XAA LCD TV
Symptom: Dead backlight flashes on then off.
Cure/Solutions: UNIT WOULD FLASH ON THEN OFF AND AUDIO WOULD WORK. YOU COULD SEE VIDEO WITH A FLASHLIGHT. SOMETIMES UNIT WOULD STAY ON AND RUN IF YOU CYCLED ON AND OFF MANY TIMES. FOUND BAD SOLDER CONNECTION ON IP BOARD TI801 ON PRIMARY SIDE. RESOLDERED AND CORRECTED PROBLEM.
Samsung: Poor or Intermittent Video
Model/s: Samsung LNS4695DX/XAA,LNS4696DX/XAA,LNS4096DX/XAA,LNS4095DX/XAA LCD TV
Symptom: Poor or Intermittent Video
Cure/Solutions: Check the LVDS cable where it connects to the panel interface board. Be sure that the cable does not have any glue on it. On occasion, the glue can cause a poor connection if it gets into the connector. Remove glue or replace the LVDS cable with BN39-00726A.
Samsung: Half screen is purple
Model/s: Samsung LNT4065FX/XAA,LNT4665FX/XAA,LNT5265FX/XAA,LNT4061FX/XAA,LNT4661FX/XAA LCD TV
Symptom: Half screen is purple
Cure/Solutions: Half screen is purple. LCD panel controller board is defective. Panel needs to be replaced.
Samsung: Video Stuttering or Hesitation
Model/s: Samsung LNT4071FX/XAA,LNT4671FX/XAA,LNT5271FX/XAA LCD TV
Symptom: Video Stuttering or Hesitation
Cure/Solutions: The customer may complain that the video has a stutter or hesitation when viewing regular programming, either standard definition or high definition.
To fix, go into the customer menu, select Picture, then scroll to Auto Motion Plus 120Hz and select Off.
This enhancement circuit works for some movies, but can introduce severe hesitations and ghosting on regular programming. The customer should also be informed that this does not affect the 120Hz operation of the panel. The panel operates at 120Hz regardless of this setting.
Samsung: Troubleshooting Inverter PCB boards
Model/s: Samsung LNT4061FX/XAA, LN32A450C1DXZC, LN32A550P3FXZC, LN32A550P3FXZX, LN32A450C1DXZX,
LN32A650A1FXZA, LN32A450C1XZD, LN32A450C1DXZA, LN32A540P2DXZA, LN32A450C1XZP, LN32A550P3RXZD, LN40A530P1FXZA, LN40A530P1FXZX, LN40A450C1HXZX, LN40A450C1DXZA, N40A750R1FXZA, LN40A450C1DXZX, LN40A530P1FXZC, LN40A550P3FXZC, LN40A650A1FXZC, LN40A550P3FXZX, LN40A750R1FXZC, LN40A330J1DXZX, LN40A650A1FXZX, LN40A450C1XZD, N40A450C1DXZC, LN40A330J1DXZA, LN40A550P3FXZA, LN40A650A1FXZA, LN40A750R1FXZX, LN40A550P3RXZD, LN40A330J1XZD, LN40A630M1FXZA, LN40A540P2FXZA, LN40A650A2RXZD,
LN40A630M1FXZC, LN40A630M1FXZX, LN40A610A3RXZD, LN40A500T1FXZA, LN40A330J1XZP, LN40A450C1XZP, LN40A650A1RXZP, LN40A610A1RXZD, LN40A650A1FXZD LCD TVs.
Symptom: Troubleshooting Inverter PCB boards
Cure/Solutions: The inverter PCB is the power supply for the Cold Cathode Fluorescent tubes. The inverter acts exactly like the ballast used in a standard fluorescent light fixture. In the case of an LCD TV, 24 volts from the power supply is applied to a switch mode power supply (SMPS). The SMPS outputs ~1000 Volts to energize the bulbs then the voltage drops to ~ 500 volts for run operation. The SMPS switching frequency is around 90 KHz. The first step for verifying inverter board operation is to confirm the 24 volt supply is present. An oscilloscope can also be used to verify the SMPS circuit is oscillating. Simply holding the oscilloscope probe in the area of the switching transformer will show screen activity if the switching action is taking place. Measuring the SMPS output with standard equipment is not recommended as this is high voltage and at a high frequency.
Samsung: Intermittent LCD Video Troubleshooting
Model/s: Samsung LNT4069FX/XAA, LNT4066FX/XAA, LNT4669FX/XAA, LNT3255HTX/XAA, LNT375HAX/XAA, LNT4042HX/XAA, LNT325HAX/XAA, LNT405HAX/XAA, LNT2353HTX/XAA, LNT3753HX/XAA, LNT2653HTX/XAA, LNT3242HTX/XAA, LNT3253HTX/XAA, LNT4042HTX/XAA, LNT4053HTX/XAA, LNT4071FX/XAA, LNT4671FX/XAA, LNT5271FX/XAA, LNT4642HX/XAA, LNT466FX/XAA, LNT4065FX/XAA, LNT4665FX/XAA, LNT5265FX/XAA, LNT2632HX/XAA, LNT2642HX/XAA, LNT2653HX/XAA, LNT3232HX/XAA, LNT3242HX/XAA, LNT3253HX/XAA, LNT3732HX/XAA, LNT4032HX/XAA, LNT4053HX/XAA, LNT4061FX/XAA, LNT4661FX/XAA LCD TVs.
Symptom: Intermittent LCD Video Troubleshooting
Cure/Solutions: Troubleshooting intermittent video problems can be time consuming, but these tips may help narrow down the cause of an intermittent video problem.
The very first thing to do is to make sure the customer does not have OSD. They can verify this by just pressing Menu or Volume on their TV remote control. If they do have OSD, then the problem is most likely in the source and not the TV.
The next step when encountering an intermittent video problem is to find out if the backlights are on when the set loses video. You can probably obtain this information from the customer before you schedule the call. Ask if they noticed if the screen is completely black or if it is lit up slightly when the video goes out. They may be able to notice it better if they stand at an angle to the TV and turn it on or off and see if there is any change in brightness.
If the backlights are out, you need to know if the set ever has video when they turn it on, or does it go out after they have had the set on for a period of time. If the set occasionally will not have backlights when it is first turned on, suspect the panel or power supply/IP board. If the set has video for a while and then loses the backlights, suspect a power supply/IP board or main board. Typically the panel will cause a no backlight at turn on, while the power supply and Main Board will cause the backlights to go out after a period of time. If the set has backlights when first turned on and the lights change their brightness in several steps before quickly going out, suspect the IP board.
If the backlights are on when the set loses video after it has been on for a while, most likely the LVDS cable is defective. If the set has backlights but no video when it is first turned on, the T/Con or Main Board would probably be at fault.
Always check the simple things first, like a LVDS cable that is not plugged in properly or a power connector to the panel being loose.
There are exceptions to every rule, but this generally should help with narrowing down no video in LCD sets.
Hitachi: No sound or audio
Model/s: Hitachi 26LD6600 & 26LD6600A, 32LD6600_A_B_C LCD TV
Symptom: No sound/audio
Cause: Sound setting may have been lost in the memory and defaulted to zero.
Cure/Solutions: Reinstate sound settings as follows:
Enter Service mode.
Press Menu then 4,7,2,5.
Go to Audio menu.
Select Sound 2. and enter the following values:
FM PRESCALER 15
NICAM PRESCALE AVL ON 35
SCART PRESCALE AVL ON 14
SCART VOLUME AVL ON 122
GO TO STANDBY TO MEMORISE SETTINGS
Hitachi: Burn in Mode when replacing Main PCB
Model/s: Hitachi 26LD6600 & 26LD6600A, 32LD6600_A_B_C, 37LD6600 LCD TV
Tip: Burn in Mode when replacing Main PCB
When replacing the main PCB on these models, the new part may be in the 'burn in' mode from manufacture. This will result in the image on screen flashing different colors.
To exit the burn in mode:
Use the remote control :
1. Press menu button
2. Press the following button sequence: 4,7,2,5 :
3. Go to “OPTIONS” and then set “BURN IN MODE” to either ON or OFF.
Hitachi: Audio noise may be heard from speakers when unit is in Tuner mode
Model/s: Hitachi 26LD6200 LCD TV
Symptom: Audio noise may be heard from speakers when unit is in Tuner mode and the volume control is set to near minimum.
Cure/Solutions: Add four SMD jumpers on the Amp board to positions J100, J101, J102 and J103 (JUMPER SMD 0603 R).
Hitachi: Retune of Digital TV channels
Model/s: Hitachi 22LD4500UK LCD TV
Tip: Retune of Digital TV channels
1. Press the menu button on the remote control to display the main menu on screen
2. Use the cursor down button on the remote control to highlight 'Installation' and then press OK
3. “Your previous digital channel list will be destroyed. Are you sure……” This message will appear on screen, select yes using the left cursor button and press OK
4. All channels will automatically be installed.
Hitachi: No sound or very low sound on terrestrial and no sound on Digital or any AV inputs
Model/s: Hitachi 22LD4500U, 22LD4500UK LCD TV
Symptom: No sound or very low sound on terrestrial and no sound on Digital or any AV inputs.
Cure/Solutions: This is a software/firmware problem. Replace memory IC302 Type 24LC16 (part number: VS20167612). All customer controls are set to minimum on the new IC. Please reset language and all picture controls to normal after replacing the IC.
Hitachi: Green horizontal line flashing across the screen intermittently
Model/s: Hitachi 22LD4200 LCD TV
Symptom: Green horizontal line flashing across the screen intermittently.
Cure/Solutions: Remove resistor R149 on the Input signal board (Signal processing-analog) and replace it with Jumper SMD( 0 ohm, partnumber: VS30001734).
Hitachi: No Switch on from standby
Model/s: Hitachi L32VP03E, L32VP03U LCD TV
Symptom: No Switch on from standby
If the TV is switched into standby when it has been running for some time and is warm, it will not come out of standby until the set has cooled completely
Cure/Solutions: Replace the crystal X104 (XTAL 14.318MHZ 20PF 20PPM SMD ROHS, part number: VS30054926) on the main pcb/main logic board, the system control section.
Hitachi: Audio is distorted constantly and may have some background noise
Model/s: Hitachi L32A01, L32A01A, L32H01E, L32H01EA, L32H01U, L32H01UA, 32LD8D20E_EA, 32LD8D20U, 32LD8D20UA LCD TVs.
Symptom: Audio is distorted constantly and may have some background noise
Cure/Solutions: Replace D845 and D846 (both UF5402 3A/200V 150A, part number: VS30009366) on the power supply board/PSU.
Collection Of LCD TV Repair Cases
PART 6
Model: AMOI 32K1 LCD TV
Symptom: No Display and No Sound
Repair/Solution:
When press on the standby mode button, LED light change from Red to Blue color but no backlight. Try to using a wire with a resistor connect the 3.3V to BL_ON signal, their backlight and screen logo AMOI are present but all front buttons and control no functions.
Remove the mainboard EEPROM IC 24C32, using a programmer to empty their Data and then solder it back to mainboard. The problem solved!
Model: Changhong LT32700 LCD TV
Symptom: TV stuck on standby mode.
After the AC power supply to the TV, standby LED light on with yellow color. When press the power on switch or remote control power on, the TV still remain the same yellow color LED light and can’t start-up.
Repair/Solution:
Check the PSU output, their standby 5V is present but no any POWER_ON signal present. Checking their mainboard voltage regulator IC output and found U1 (LM1084-2.5) output voltage as 4V! Actually it should be output 2.5V instead of 4V. After replace U1 the TV is working now.
Model: Hisense TLM3237D LCD TV
Symptom: TV Power On then Shut Down
Repair/Solution:
Check the PSU board standby 5V STB normal and stable. But their POWER_ON signal is unstable, change in between 0~4.8V. Normally this POWER_ON signal is about 4.6V for this TV. So the problem was in mainboard or CPU section. Check their mainboard Voltage Regulator IC output voltages all normal and stable. Empty the U11 (24C32) EEPROM but not help. Testing the SCL & SDA line voltages it shows in between 0V~3.3V. Test the crystal Y2 (14.318MHz) it have 1.5V and another side is 1.7V. Use the ISP Programmer to program the correct version firmware into the mainboard flash memory U10 (PS25VF040). Power on the TV and the TV is working! After that, using remote control to control the TV function and their setting but it is hard to operate and slow motion to change function. Power off TV and then power it on again, the TV back to their original fault! Replace a new flash memory U10 (Cannot use the empty flash memory and it will can’t start-up the TV, must using the ISP Programmer to copy their firmware into it) and solder it back to mainboard. Finally the problem solved!
Model: Hisense TLM40V68PK LCD TV
Symptom: 1) Pop up OSD Menu Randomly
2) Front panel buttons sometime no function
3) When TV in standby mode, can’t use the remote control to power on (start-up) the TV.
4) Auto power on of power off the LCD TV.
Repair/Solution:
All these symptoms were causing by the ESD protection component call it as MLV (Multi-Layer Varistor). It is look like a small SMD diode and its function as an ESD protection & surge noise. How to testing it? Yes, this type of components normally they are using much in mainboard. So you can use the diode range to compare their values. If one of that MLV values different much or shorted, then you can direct remove it and power on the TV. If the problem solved, then you can find another MLV from a junk mainboard to replace it.
Conclusion: No wonder what brands or models of your LCD TV, if you’re facing the above LCDTV symptom and haven’t find out what was wrong, then you can try to check these MLV components inside their corresponding circuit lines. Some time on the signal input line, it is not one MLV defective, but maybe 2 or 3 units. For example, I had repaired an LCD TV with VGA port signal input no display problem. After checking their signal R, G, B, SDA & SCL lines got 3 MLVs shorted. Normally one MLV will using in one signal line, but this LCD TV VGA input signal got 3 MLV of them shorted and affect the VGA mode no display symptom.
Model: Konka LC32ES62 LCD TV
Symptom: TV Randomly Can’t Start-up, LED light blinking non-stop with Red and Green color). Or when TV heat the backlight flickering till no backlight/cut off and the sound remain ok.
Repair/Solution:
This TV is using the IP (Inverter Power Supply board) board with LG LCD Panel. Find a resistor R756 in IP board and modify it to 3.3K ohm and problem solved.
Model: LG 32LG30R-TA LCD TV
Symptom: Stuck in standby mode
Repair/Solution:
When the AC power on, Red LED light lit. Using remote control to power on the TV, LED light change to Blue color but PSU no 12V, 16.5V & 24V output. PFC big filter capacitor has 380V there. Remove the ZD111, ZD112 & C108 on the PSU board near U102 (NCP1396A). It is a power supply design bugs, so after remove these components, problem solved.
Model: LG Chassis LA73A LCD TV
32LB4DS-UA, 32LB9D-UA, 32LB4DS-UA, 37LB5DF-UC, 42LB5DF-UC, 47LB5DF, 47LC7DF-UB, 47LY3DF-UA, 52LB5DF-UC
Symptom: a) Auto Power on and Power Off
b) Auto Channel Up and Down
c) Auto OSD Menu display
Repair/Solution:
Check or replace EMI filter on these location: L729, L730, L741, L742, L743, L744, L746, L747, L751, L752, and L753.
Model: LG 42LK520-UA, 42LK530-UA, 42LK550-UA LCD TV
Symptom: When power on the LCD TV, there is no display
Cause: Because the Height of embo is low, when assembling C/PCB to the module, it can have a scratch on the bottom on T-con board.
- Thermal pad press the C/PCB
- PCB bottom (scratch point) is short with C/Bottom (Ground)
- Because of the over-current, it will make the mainboard damage.
Repair/Solution:
Temporary solution is to add isolation cushion sheet between Embo and C/PCB.
Model: LG 32LG700H, 37LG700H & 42LG700H LCD TV
Symptom: Power itself On/Off.
Cause: Touch IC sensor malfunction
Repair/Solution:
IR assembly C104 change from 2pF to 12pF.
Model: Philips 20PF5120/93 Chassis ML1.1A AA LCD TV
Symptom: Randomly No Display but Sound Normal
Repair/Solution:
Find this R54 (54.9K ohm) resistor and replace it with a 75K ohm resistor on mainboard.
Model: Philips 32PF7321/93 Chassis LC4.31A AA LCD TV
Symptom: Sound Distorted
Repair/Solution:
Replace 2013 ceramic capacitor from 1.5nF to 10nF/50V ceramic capacitor.
Model: Philips 42TA2000/93 Chassis TPT1.0A LA LCD TV
Symptom: Display and Backlight flickering
Repair/Solution:
If capacitor on position 2083 positive pin is 24V and drops to ~20V, so measuring the capacitor on 2079, 2081 & 2082 with ESR tester or replace these 4 capacitor at the same time and problem solved.
Model: Samsung LE40R76B LCD TV
Symptom: Some vertical lines on the TV screen. But sound is ok.
Repair/Solution:
Check the PSU output voltages all ok. After that checking their T-con board Vcc input and Voltage regulator IC. Found that 2.5V Voltage Regulator IC no output. After replaced it the TV screen is ok now.
Model: Samsung UNxxC9000 LED TV
Symptom: The UNxxC9000 LED TV power up sequence
Repair/Solution:
This power up sequence can help you troubleshoot the UNxxC9000, here is the power up:
a. When the AC cord is plugged in, the voltage on the STBY pin goes to 5.3V.
b. The MCU (Microcontroller, Micon &etc) on the mainboard actively looks for the user to press Power On switch from remote control or the TV itself.
c. When a user presses Power, the MCU sends a “High” voltage (0-1.2V transition) to the SMPS/PSU via Power_On/Off pin to activate the rest of the voltages.
d. After the 0-1.2V transition on the POWER_On/Off pin, the following voltages are activated on CNM801 and the “Melody” plays.
- Vamp= 18VDC
- OD_On/Off= 3.3V
- D5.3V = 5V
- D12V = 13V
e) Approximately two seconds later, 5V is applied to the BLU_On/Off pin.
f) Once the BLU_On/Off pin is activated, the LED arrays turn on. CNL801 supplies high voltage to the LED arrays. The following voltages are activated on CNL801 (with respect to chassis GND):
- BOT1+ = 170VDC
- BOT1- = 45VDC
- TOP1- = 45VDC
- TOP1+ = 170VDC
- TOP2+ = 170VDC
- TOP2- = 45VDC
- BOT2- = 45VDC
- BOT2+ = 170VDC
g) High voltage is applied to the panel LED arrays though connectors CN401 and CN402:
Pin 1 and 12
-Approximately 170VDC (when referenced to the chassis GND).
-Voltage varies when referenced to connector GND.
Pin 6 and 7
-GND (effective).
-Approximately 45VDC when the backlight is lowest.
-GND Pins
-GND Potential is highest when signal is >90% duty cycle (almost DC).
-GND Potential is lowest when signal is <10% duty cycle (almost GND).
-Level is controlled by the mainboard though the Bot_Dim and Top_Dim pins on connector CNM801
Model: Samsung LN19C350DXZA LCD TV
Symptom: Display is completely Green color only.
Repair/Solution:
LVDS cable not properly inserted or dirty in the contact pins. Clean the LVDS cable contact pins and connect it back properly.
Model: Samsung UN46C6300SF LED TV
Symptom: No Power
Repair/Solution:
This ICB801 (ICE3BR1765J) Power IC is defective on the PSU board.
Model: Sharp LC26SA1E, LC26SD1E, LC32SA1E, LC32SD1E, LC42SA1E, LC42SD1E LCD TV
Symptom: No Display, Sound Problem or Various operational key issues
Repair/Solution:
If after checking the whole PCB boards in TV still not solve the problem, it could be software issues.
Update the main software to the latest version, following the instructions in the service manual. Or using an ISP Programmer to empty their EEPROM IC first, if problem still the same, then you should program their flash memory by ISP Programmer with the working firmware.
Model: Sharp LC46D78UN & LC52D78UN LCD TV
Symptom: HDMI Connectivity Issues: No Sound or No Display When Turned On
In some cases, when connected via HDMI to an external audio amplifier or set top box an interruption to the sound and display may result when the TV us turned off and back on. This may occur due to current leakage from the HDMI-SW IC VHISII9287+-1Q on the mainboard.
Repair/Solution:
When the TV set requires service due to the above mentioned symptom, replace C1614 (0.1uF, 104 ceramic capacitor) on the mainboard with a 1K ohm1/16W resistor to reduce the leakage effect or just replace the mainboard.
Model: Sharp LCD-37GA5 LCD TV
Symptom: Stuck in Standby mode.
The LED light lit with Red color and its show on standby mode. Even press the power on button or using remote control also cannot power up the TV.
Repair/Solution:
After testing the PSU board, their standby 5V present and BL_ON signal (3.16V) was sent from mainboard to inverter board. And then their main chipset, Vcc voltage, clock or crystal waveform and reset circuit all normal, so that’s mean their main chipset is working properly. But their POWER_ON signal is missing and not present on the switch transistor to drive the RL701 to start-up the PSU.
From the previous experience, if all section in good condition but still no start-up, then it could be their MCU chipset or external flash memory (or their firmware corrupted) defective. Because of the Sharp LCDTV have lots of this problem was causing by their flash memory firmware corrupted. So checking the flash memory firmware first and found it was in IC3001 (L64) position. After solder it out, using an ISP programmer to backup their original firmware first. In case it is not the flash memory problem, then you can program it back to original version firmware. After that, find a correct version & working firmware and using the ISP programmer to program it into the L64 flash memory IC. Solder back this L64 flash memory into the mainboard. Power on this Sharp LCD-37GA5 LCD TV and it is working perfectly now! Problem solved and confirmed it was the firmware corrupted till it can’t start-up the power supply.
Model: Skyworth 24E60HR LED TV
Symptom: No Backlight or Display Dim
Repair/Solution:
This symptom is a common fault for this LED TV. Their problem was causing by LED Inverter/Drive board. When testing the LED Drive board C1 voltage, it is just 24V only. That’s mean their LED Drive board not working. Try to re-solder the LED Drive board U01, U02 and their surrounding components. After solder the board, their LED backlight is working now.
Model: Skyworth 55LED10 Chassis 8K81 LED TV
Symptom: Hard to start-up the TV when first time power it on.
When this LED TV every day first time power on, it is hard to start-up the TV. Check their 24V is ok but 12V output just have about 6~7 V only.
Repair/Solution:
This TV is using the ChiMei lcd panel and their PSU board is use 168P55PTQC-00. The PSU 12V output is from 24V through a DC-DC circuit generated. Change the R212 from 10 ohm to 0 ohm and R214 from 10 ohm to 4.7 ohm.
Model: SONY KLV-26S550A, KLV-32S550A, KLV-37S550A LCD TV
Symptom: Flashing and Jittering Display
When watching certain channels in RF mode, the picture may be flashing and jittering intermittently.
Cause: Abnormal signal condition- the problem channel has a wider H-sync width compared to the SECAM standard signal (difference up to 1,2us)
Repair/Solution:
Update the firmware to the latest version. In case of a 32 inch panel, first check the panel type before updating.
Model: Sony KLV-32G480A LCD TV
Symptom: No Display but sound ok and backlight working.
The screen has a “TV” character on the screen but no display, just black screen.
Repair/Solution:
Since this LCD TV sound and backlight ok, so the problem should be on the mainboard. Using volt meter testing the T-CON board Vcc line and it has 12V there. So the problem could be the mainboard Scaler IC, MCU, Flash memory, EERPOM or T-CON board. After testing the Scaler IC & MCU corresponding circuits like reset, Vcc and crystal all looking well. So try to check the flash memory & eeprom IC. Found these ICs were beneath of the mainboard. The IC3001 is 25L08 flash memory IC and IC3002 is 24C64 eeprom IC. So start the easy one, remove IC3002 (24C64) and using programmer to save their original data first and then erase this eeprom IC till it empty and all show “FF” on the programmer software. Solder 24C64 eeprom IC back to mainboard and power on the LCD TV. The TV screen can show a perfect display now and problem solved!
Model: Samsung LA32R91B LCD TV
(This repair tips was contributed by Mr. Behzad Sedigh. Thanks Beh!)
Symptom: TV brightness and contrast features automatically change to 100% (maximum).
Even using the remote control adjusts it to 50%, but in a short time it will automatically change to 100% of brightness and contrast.
Solution/Cure:
Found some bulged electrolytic capacitors on the line of DC supply to mainboard. After replaced these electrolytic caps, the symptom was getting better but not completely. Even disconnect the front control panel and checking their circuit line till mainboard also normal. It is no any leakage ceramic caps in that circuit line. So it will suspect the flash memory, eeprom IC or the MCU. So starting from the easy way first, checking the eeprom IC. This eeprom IC is beneath of the mainboard and it is using 24C256BN (SMD SOP-8, 8 pins IC). Yes, this eeprom IC (AT24C256C) can be as a replacement for 24C256BN. After replaced a new blank eeprom IC, the Samsung LA32R91B LCD TV problem solved!
Model: V315B3-C01T-con Board:
a) Symptom: TV No Display but Sound Ok and the backlight working.
Check the T-con board and found that SMD fuse burnt. If this type of symptom doesn’t just put another fuse to power on the TV, it may damage seriously again.
Repair/Solution:
Since the SMD fuse burnt, must using the Multimeter checking Vcc input line with GND ohm values. The values show it is normal, continue checking the other voltages lines like VGL, VGH, VDA & etc. Finally found VDA line to GND was shorted and it was 0 ohm. Disconnect the both FPC cables, VDA line still remain shorted. Now checking their VDA line corresponding components and found the CP12 shorted. After remove CP12, VDA line ohm values back to normal and testing this CP12 was confirm it had shorted. After replace SMD fuse and CP12, the VDA output 15.9V and TV is working properly.
b) Symptom: No Display but Sound Ok and the backlight is working
Repair/Solution:
Check the Vin have 12V input and other voltages lines also normal except VDA line is 0V. Because of the T-con board DC-DC voltage control by the timing control, as follows: VDD25, VDD18 => VDA => VGL =>VGH, the VDA is control by TPS65161 pin 27 output logic high/low signal (voltage) to QP1 (P-ch MOSFET) pin 4, when signal logic low received the MOSFET is switch ON and the VDA voltage has output and reaching to the GAMMA correction IC.
Test the QP1 MOSFET, pins 1, 2 & 3 have 15.9V. It had proved that the VDA voltage is present. Testing MOSFET pin 4 is logic low signal, but pins 5, 6, 7 & 8 no VDA output! Remove and testing the QP1 MOSFET and found it had opened circuit. After replace QP1, the VDA got 15.9V output and display back to normal.
Note: If don’t have the QP1 on hand, temporary can just using a wire connect QP1 pins 1 and 8, so it will bypass the QP1 switch function and testing T-con board is ok or not.
c) Symptom: Screen Shows Vertical Color Stripes. The stripes are slowly to increase.
Repair/Solution:
The vertical color stripes is slowly increase till full screen of vertical color stripes. This symptom could be the VGH circuit abnormal. Check the VGHP has 21V but VGH is 0.3V only instead of 21V. Testing QP7 (2N7002) pin 2 is logic high, pin 6 has 21V. For testing purpose, try to using a wire connect QP7 pin 6 to pin 4. After connected the wire, the VGH has 21V output now and display show perfectly. After replace the QP7, display is working properly now.
d) Symptom: Screen Fully of Vertical Stripes and Sometime NO Display
Repair/Solution:
From the above symptom, it could be one of the DC-DC circuits abnormal and causing this problem. Check the DC-DC circuits and found that VGH voltage not stable and it is about 4.6V only. After some time, the DC-DC circuits all voltages will no output (No Display) and need to power off and then on it again the voltages will come. When the no voltages output, power off the TV, using the finger touch the IC and feeling their temperature is a bit high but not extremely hot. Suspect the FPC cables problem; remove both CN1 & 2 and measure the VGH voltage still not stable. So the problem is still in VGH circuit line. Check the VGH line corresponding components, by disconnecting the CP19, CP43 and found that when removed CP43, the VGH voltage line is back to 21V! Replace CP43 with 1uF/50V, the T-con problem solved.
Model: Changhong LT2612 LCD TV (T-con: SVA 260PW023S)
Symptom: No Display and the screen full of Vertical color lines
Repair/Solution:
Normally this type of TV symptom was causing by the T-CON board or LCD panel. This LCD Tv using SVA 260PW023S T-CON board. Check the T-con board Vcc voltage input had 5V, and the AVDD had 3.3V. The lcd panel driving voltage VGH & VGL are nothing. Suspect their DC-DC circuit lines having problem. Check the VGH line with GND with ohm range, it had 300 ohm only. But VGL line with GND had above 36K ohm! So suspect the VGH circuit line filter capacitor leakage. Found three SMD chocolate color filter caps on the VGH line and two of three filter caps were leakage, another good one got 3.3uF. Because of they are three same size and color filter caps, so using one normal electrolytic capacitor 10uF/50V to replace it. Power on the TV their display is back to normal now.
Model: Changhong LT24720FX LCD TV
Symptom: Display poor image with whitish tail or ghosting
Repair/Solution:
Normally this type of symptom was causing by the T-CON board or LCD panel. So starting testing their T-CON board voltage and found that VGH voltage has 2.3V only. The correct VGH voltage for this T-Con board should be about 25V. At the same time found a burnt component on the T-con and the location is R100. That’s mean it is a burnt resistor and can’t saw any value there. Using multimeter ohm range to checking the R100 pin ohm values to GND (ground) is about +/- 500K ohm. This is let us know, the R100 position not because of other components short circuit and causing it burnt. Use a 1M ohm variable resistor (VR), starting from the highest ohm first and then slowly decreases the ohm values until the VGH reach 25V and the display also change to normal. So check on that VR and found it is about 100K ohm, after that changed a SMD resistor with values 100K ohm to R100. The VGH line got 25V now and the display image also back to normal now. The TV problem solved!
Model: ChiMei V320B1-L06 LCD Panel with T-con board V320B1-C03
Symptom: Screen fully with Vertical Color Lines
Repair/Solution:
This T-con board Vcc voltage is present. Check VDA voltage is 11.2V only. That’s mean their DC-DC circuit not working. Since their DC-DC IC AT1380A is control by the Timing Control chipset (CM2681A), when checking their switch on signal from CM2681A, it is no any signal from it. After that checking the CM2681A voltage supply IC N7 (2.5V voltage regulator IC) and found that has 0.9V volt output only instead of 2.5V! After replace this N7 IC , the screen is back to normal now.
Model: Hisense TLM-3233D LCD TV
Symptom: No Display but Blue Screen with Two Vertical White Bars
Repair/Solution:
When power on this lcd tv, the screen show no display but blue screen with two vertical white bars. The two vertical white bars will flash but no any content inside. The LCD TV can hear the sound and remote control to change channel properly. Try other video signals input like AV and PC also same results. Even try to call out the OSD menu also same problem too.
Since the LCD TV cannot show the OSD menu and the TV got sound and change channel properly, so that the mainboard is normal. After observation this lcd tv, found that the problem could be in the T-CON board or LCD panel.
Check LVDS and FPC cables, they are show as normal, then check the T-CON board voltages. All voltages in T-CON board are ok, so that i will suspect the T-CON board mainchip (N39) or their memory chip (N31) defective. I got the junk T-CON board with same part number, but their DC-DC chip was burnt. So the mainchip and memory IC can be use. Because of the N39 (CM2681) have many pins and the memory IC N31 (24LC128) only have 8 pins, so that I choose to replace the N31 first. After replace the N31, I try to power on the TV, and it was show display perfectly!
Since this N31 is a memory IC, does that mean IC itself damage or just the firmware corrupt and caused this problem happen? To find out this answer, I use my programmer to copy the working memory IC firmware and write it into the original memory IC. Do you guess what has happen? Yes, the LCD TV working perfectly too! So the problem solved and it was causing by the firmware corrupted.
Conclusion: The T-CON board memory chip or their firmware corrupt also can cause the screen problem. So that we need to save their firmware and must prepare some junk boards of T-con board, mainboard and inverter board for future use.
Collection Of LCD TV Repair Cases
PART 7
Model: Hisense TLM3226 LCD TV (T-CON: ChiMei V320B1-C03)
Symptom: No Display
The TV sound normal and it can control by the remote control. Backlight is present but the screen no display and look like grey screen (because the backlight was working).
Repair/Solution:
This lcd panel using ChiMei V320B1-C03 T-CON board. So first check their Vcc input and other voltage values. Vcc input 5V ok, voltage regulator output 2.5V & 3.3V normal. When measuring the VDA, VGH & VGL voltage found all not output 0V only.
It was shows that their DC-DC section is not working. After analysis the ir DC-DC section, it is using the UP1 IC (AT1380A) as a DC-DC IC. The UP1 pin4, on/off switch is control by the T-CON main chipset U3 (CM2681A-KQ) pin 63.
Usually when the TV on, T-CON board IC U3 (CM2681A-KQ) pin63 (PWRON) will output a signal logic high (3.3V), through QP3 inverse the signal to logic low and reach to UP1 pin4. After that, UP1, DC-DC section starting working and generates VDA, VGH & VGL voltage outputs.
But for this T-con board, even the TV was power on, but their U3 (CM2681A-KQ) pin 63 still is logic low 0V. Normally this U3 pin 63 will follow by TV power on and off, their voltage range is between 0V~3.3V. Even disconnect the U3 pin63 with other corresponding components, this pin63 also not different still 0V. Suspect their U3 (CM2681A-KQ) damage, after replace U3 the TV was back to normal now.
Model: Hisense TLM3201 LCD TV
Symptom: No Display but sound and other function properly.
Repair/Solution:
This model of LCD has using two type of LCD panel. These LCD Panel are QD32HL01 and another one is QD32HL03.
For this LCD TV symptom, no display, the QD32HL01 LCD panel their T-CON board Q300 open circuit causing the TV no display. This Q300 function as an on/off switch for DC-DC section. Direct replace Q300 with FDN339AN and the problem solved.
For the LCD panel using QD32HL03, their T-CON board D304 (BAV99LT1) opened circuit and causing the TV no display. This D304 is using on the VGH circuit line. After replace D304 the TV problem solved.
Model: Hisense TLM40V68P LCD TV (T-CON Board: V400H1-C01)
Symptom: Display White Screen only.
The other function like sound and remote control are ok and working properly.
Repair/Solution:
This LCD TV panel take a bit long time to start-up the display. But the TV display white screen only. Since all other function normal, so the suspicion section is the T-con board.
Starts measuring this T-con board and found that their VGHP voltage is missing, 0V but other voltage testing points are normal. Normally this VGHP has about 19.5V. Power off the TV, using Multimeter ohm range to measure their VGHP point with GND and the values is 0 ohm! That’s mean the VGH P circuit line has component shorted. First check the circuit line filter caps, when remove that capacitor CP19, the VGHP circuit line ohm values are back to normal. After testing this CP19 and found it was shorted. After replace CP19 on the T-con board, the problem still remains the same! When checking the VGHP circuit line, it is still 0V. Forward to UP1 pin10, here can measure the 2.25V and 5VAC output. VAA testing point has about 13V, so to confirm that the DP5 is open circuit. After removed DP5 and using Multimeter to testing this component, double confirm that DP5 is opened circuit. After changed both components, the TV appear the display perfectly.
Model: Hisense TLM4288 LCD TV
Symptom: Screen fully of vertical color lines and then no display.
When power on the TV, it is ok but after half an hour, the screen was changed to vertical color lines. And it also appears some horizontal bar on the screen. Some time it can back to normal and change to vertical lines and then the TV no display. But their sound, backlight and the remote control, all function working properly.
Repair/Solution:
For this LCD TV symptom, so the suspicion parts will be the LVDS cable or their T-con board problem. This TV symptom was because of the mainboard LVDS signal are not match with timing control in the T-con board. First checking the LVDS cable both sides contact pins are clean and no any dirty on the pins. After that checking their cable continuity and it is ok. So the other part is the T-con board.
After testing T-con board all voltages normal and stable, so the problem should be in the LVDS connector and their signals processing section. Since this TV symptom was occur after half an hour, so it could be the components dry joints or heat sensitive. So after power on the TV, try to using a plastic rod to pressing the T-con. When the plastic rod pressing on the LVDS connector socket, the TV screen back to normal! So the culprit is the LVDS connector socket dry joints. After resolder the LVDS connector socket, the LCD TV is ok, even after burn test about 4 hours it’s still working properly.
Model: LG LC370W01-A5K1 T-con Board
Symptom: Grey Screen, No display
Repair/Solution:
This T-con board Vin is use 12V as input voltage. Found their Vcc input SMD fuse KT opened and looks like other components has shorted in the circuits. Measure the Vin line ohm values is normal. After that checking the other voltage output lines ohm values and found that VDD with GND has 0 ohm! That’s mean something was shorted to ground. Finally found that C130 filter cap was short circuit. After replace SMD fuse KT and C130 filter cap, the TV is back to normal.
Model: LG LC420W02-B6 LCD Panel with 6870C-0046B T-con Board
Symptom: Screen Show Negative Display with Full Red Color
Repair/Solution:
The LVDS cable is ok. For this type of display symptom, you must try to slowly minimum the Contrast feature. If after minimum or closed the feature of Contrast and display back to normal (have colors), that’s mean, the problem was in the T-con board and it is causing by timing control not working properly. If after minimum the Contrast feature, the display is missing color, so the problem was in the mainboard. Since this is T-con board problem, so concentrate to testing it. Normally if Timing Control section work, it must have: 1) Correct Vcc input (from DC-DC section supply), 2) Panel setting (this setting data was store in the EEPROM IC), 3) Data communication EEPROM with Timing Control IC must stable. 4) If the Timing Control IC defective it also can effected. Their voltage input is normal and corresponding components also no problem. So try to find another junk board to remove both EEPROM U2 & U5 (both 24Y02) to this T-con board. After power on the TV, yes the problem solved!
Model: Sony 37 inches LCD TV with AUO T370XW02 T-CON Board
Symptom: The Character normal, but the picture area when it is bright, their edges got other color banding.
Look like the LVDS cable contact problem. When it is brighter, their symptom becomes serious. If turn the Contrast down to 50%, the character and picture back to normal! From this method we know that it is not the mainboard problem but it could be LVDS cable or T-CON board.
Repair/Solution:
Check the LVDS cable both contact pins and also using an eraser to wipe clean both side. But it is not help. So suspect the T-CON board problem. From the symptom on the screen, if the problem is T-CON board, then it could be their Gamma circuit’s lines problem.
Found this T-CON board had 22 testing point, GAMMA1~GAMMA22. Where their normal GAMMA circuit lines voltage level are decrement way. After testing their voltage points, found GAMMA1 till GAMMA20 are using decrement way it was from 15V till 3V, but the GAMMA21 voltage point was about 8V! It should be 3V or below. Tracing this GAMMA21 line and it is from the AS15-F DC-DC & Gamma IC. So trace this line corresponding components, but all looks good. So decide to replace the IC AS15-F and problem solved!
Note: The AS15 series of DC-DC IC (14+1 Channel Voltage Buffers IC) have higher damage rates on the T-con board. When you check the T-con board with this IC, power off the TV and use the finger touch on this IC. If you feel it is warm only, then it should be good. But if you feel it is extremely hot on the IC surface, that’s mean this IC is gone and need to be replace. The AS15-HG can use as an equivalent of AS15-G and same as the AS15-F & AS15-HF. Their different is only theAS15-HG built in the heatsink inside bottom of IC body.
Model: Sony KLV32S400A LCD TV
Symptom: Negative Picture, Display Distortion or White Screen
This model of TV has the above symptoms and all are because of their T-con board problem.
Repair/Solution:
This model LCD TV, their T-con board has very high damage rates on the U6 IC (AS15-F or AS15-xx series IC). When power off the TV, try to use the finger to touch U6 IC and you will feeling it is extremely hot! After replace this IC, the problem solved.
Model: ACER AL2671W LCD TV
Symptom: Dead.
Repair/Solution:
After change power supply IC (TNY264PN) and resistor R60 (10R/0.33W,
NFR type) the problem solved.
Model: ACER AL2671W LCD TV
Symptom: No start-up and the LED light is orange color.
Repair/Solution:
After changed capacitor C380 but the problem remains the same. Standby PSU
functions and standby 5v present. The voltage appears at pin PSON in the PSU
after switch on but PSU does not start. Actually they are three 330K SMD
resistors in series in the PSU which supply voltage for DLA001. Check if
resistors are high resistive values.
Model: Acer AL2671W LCD TV
Symptom: No start-up. Orange LED light.
Repair/Solution:
Check C380 (100uf.16v) under heatsink, next to U42 and U61 on signal PCB
for capacity loss.
Model: Acer AT3201W LCD TV
Symptom: No function on user control and remote control.
When SCART module has been removed remote control reaction ok.
Repair/Solution:
Replaced electrolytic capacitors C348 and C350 (both 220uF/16v) on
mainboard.
Model: Bush IDLCD26TV05HD Chassis L9 (Beko) LCD TV
Symptom: No backlight and no picture. Sound ok and can be intermittently.
Repair/Solution:
Replace C512, C513 (both 1000uF/35v) and C519 (220uF/35v) in PSU. Change
a 1000uF/16v capacitor on the signal board. The location of this capacitor is on
the far right-hand side near the top of that board.
Model: BUSH LCD26TV006HDX LCD TV
Symptom: No display. The standby LED light is flashing.
Repair/Solution:
The capacitor C315 (1000uF/25v) is supplied higher rated, and it is a little
bigger so use longer leads don't fit close to board. Be careful when soldering
you don't accidentally remove the tiny surface mount resistors on back of board.
Model: BUSH LCD32TV005HD APH000 Chassis BEKO LM LCD TV
Symptom: Picture appears for a few seconds after switch on, and then the TV
switches off again.
Repair/Solution:
Check C2042 and C2044 (both 680uf/35v) in PSU for capacity loss or bad ESR
value.
Model: BUSH LCD32TV005HD APH000 Chassis BEKO LM LCD TV
Symptom: No Picture and no backlight. The TV front control buttons were
working but remote control does not function.
Repair/Solution:
Replace IR receiver, where this part is short circuit.
Model: BUSH LCD32TV022HD with 17MB15 Chassis LCD TV
Symptom: Intermittently no start-up or dead after a few hours.
Repair/Solution:
The PSU replaced and EEPROM IC re-solders, but not helps. Try to re-solder
IC220 (SDA5550) and IC224 on main board the TV is back to normal.
Model: Bush IDLCD26TV05HD Chassis L9 LCD TV
Symptom: No Backlight
They are no 24v to the inverter board after a while. Sensitive to power supply
tapping.
Repair/Solution:
Check & replace SMD 27v zener diode (red with yellow bands). The diode is
located in primary side of the 24v chopper transformer supply, near pin5-8 of
the SMD POWER IC (UC3843A). This PSU board part number is GDP002
ZR1910R NETZTEIL SPS 180W 24/5 12/5 PFC 2pin (LISH).
Model: Changhong LT2618 LCD TV
Symptom: Stuck in standby mode.
The power LED light is red colour only. Check their standby voltage on J806
pin 4 & 5 is about = 5.2V, that’s mean the PSU has been supply 5V to the
mainboard. Using the remote control to start-up the TV and found that socket
J806 pin 1 received an ON signal and it is sent from CPU. That’s mean the CPU
is working properly. Testing the power supply secondary out voltage for 24V
and 12V lines both also = 0V. So the TV can’t start-up is not causes by the
standby section, that is PSU primary section. Check the power IC IC801
(STR6759N) pin 4 (Vcc) is about ~11V. Continue checking the 12V & 24V
lines corresponding components.
Repair/Solution:
Finally found that 24V output voltage was shorted to ground and the failure
component is D841 shorted. After replaced D841 the TV is start-up and
working properly now.
Model: Changhong LT4018P LCD TV
Symptom: Dead.
Normally this type of problem is causes by the PSU section or their output
voltage loading side short circuit. Check PSU primary side has 300V there but
nothing on secondary output. After power off TV, testing each voltage output
lines with multimeter ohm range and found that the +5V line was shorted to
ground.
Repair/Solution:
One by one disconnect the line was connected to +5V source and found that the
USB module has been short circuit. Disconnect the USB module and power on
the TV, the TV is working properly. Try to checking the USB module and
found their cables connect between mainboard and USB module was shorted.
After replaced the USB module cable the TV is fully working now.
Model: Changhong LT3218 LCD TV
Symptom: Display white screen, but sound ok.
This LCD TV is using the AUO LCD panel. Where their T-CON voltage supply
Vcc is using 5V. Testing their actual VCC voltage was show 4.7V only. Suspect
the Vcc voltage is a bit out of their range, then using the external 5V connect to
T-CON. Power on the TV and the display is ok now.
Repair/Solution:
Check the T-CON Vcc pin corresponding components and found that C504 is
leaking and need to replace a new one. After replaced C504, this TV is ok.
Model: Dell W2600 LCD TV
Symptom: OSD Menu locks after 10 minutes
Repair/Solution:
Change regulator IC (LM1117 DT-2.5) on mainboard.
Model: Dell W2600 LCD TV
Symptom: Intermittent or Erratic functions.
Sometime the TV locks-up problems, shuts down, no start-up and no remote
control or front panel functions.
Repair/Solution:
Re-solder or reflow system ROM chip IC1234 and all regulators IC on the
mainboard.
Model/s: Dell W2600 LCD TV
Symptom: No start-up after warm-up.
Repair/Solution:
Replace capacitor (10uf/50v) on small board mounted to power supply next to
mainboard power connector.
Collection Of LCD TV Repair Cases
PART 8
Model: EVESHAM ALQEM37SX with 17MB15 Chassis LCD TV
Symptom: No start-up, the TV screen lights up, then switches back to standby
mode.
Repair/Solution:
Please check or direct replace the C877 and C878 on PSU board for open
circuits. Sometime these caps will check well, but would breaks down when
under load.
Model: GOODMANS GTV26WLCD LCD TV
Symptom: Shuts down and LED blinks.
Repair/Solution:
Replace the C877 and C878 (both 15nF/630V) near heatsink, at top left corner
of PSU.
Model: GOODMANS GTV32W22HD AVZOOO Chassis LM LCD TV
Symptom: Dark picture. OSD bounces.
Repair/Solution:
Replace the C2042 and C2044 (680uf) in PSU.
Model: Grundig GULENAR32HDIP with Chassis L9 LCD TV
Symptom: Stuck in standby mode, LED light is blue color.
Repair/Solution:
The blue LED always stays on, even when appliance is on standby mode.
Capacitor C931 (1000uF) replaced but the TV is still dead with 12v and 24v ok.
Check and replace diode D300 on the right-hand side, on middle-top of the
main board. The problem solved.
Model/s: Hisense LCD4204EU LCD TV
Symptom: Dead after a Bang Noise.
Repair/Solution:
Replace chopper drive STRX6769, RE038 (10R) and RE032 (150R) in primary
PSU.
Model: Hisense TLM4788P LCD TV
Symptom: Dead.
TV power on, testing the PSU secondary output voltage +12V, +5V_M & +24V
all are = 0V no output. After that, testing the standby voltage +5V_S also same
as 0V! That’s mean it was the standby voltage supply section malfunction.
Checking the NE521 (STR-A6351) pin 7 & 8 has 300V, but pin 3 is 0V.
Normally this Power IC Vcc pin has about 15V.
Repair/Solution:
Check the corresponding components on Vcc line and found that RE523 was
open and other parts are normal. Replaced a new RE523 resistor, the TV is ok.
Model: Hitachi 32LD6200_A_B_C LCD TV
Symptom: Set fails to power on/switch on.
If MB11-6 Main board is used instead of the original Main board MB11-2 the
unit won't switch on.
Unit switches off immediately and a clicking noise comes from the Power
Regulator Board.
Repair/Solution:
Replace the LVDS cable (p/n: VS30041693) and add a 47uF (p/n: VS30000396,
CAP EL47UF16V) electrolytic capacitor to Power Regulation Board.
Model: Hitachi 32LD6200_A_B_C LCD TV
Symptom: Unit does not switch on or fails to power on.
Unit does not work, standby LED not lighting.
Cause: Working of Pixelworks controller IC21 depends on ambient
temperature. If IC is heated externally the unit starts to work normally.
Repair/Solution:
Replace Ferrite bead L500 and L501 with a jumper wire without the ferrite rod.
Model: Hitachi 32LD6600_A_B_C LCD T V
Symptom: No picture, but sound ok.
Cause: Dry joints on components S627 and S629 near connector PL308 on the
main board.
Repair/Solution:
Re-solder components S627 and S629; also check other components for dry
joints near the connector.
Model: Hitachi 32LD7200 LCD TV
Symptom: Distorted Sound/Audio.
Sound is distorted when the set is first switched on. After a while the fault clears
and the set works normally.
Repair/Solution:
Try to re-solder first, if still the same then replace Joint PWB. p/n: TP01336.
Model: Hitachi 32LD7200 LCD TV
Symptom: Mechanical Noise from Screen in Dynamic Mode
Cause: Low back light setting on Dynamic mode.
Backlight settings are different for each mode:
DYNAMIC: 12
NATURAL: 15
CINEMA: 10
Repair/Solution:
Increase backlight settings in Dynamic mode from 12 to 20.
If similar noise problem occurs on other modes, adjust backlight levels to the
position in which noise becomes the minimum.
Model: Hitachi 37LD6600, 37LD6600A LCD TV.
Symptom: Mechanical Noise from Screen Only in CINEMA MODE
Cause: High back light setting on Cinema mode.
Backlight settings are different for each mode:
DYNAMIC: 00
NATURAL: 50
CINEMA: 100
Repair/Solution:
Reduce backlight settings in Cinema mode from 100 to 59 as follows.
Enter Service Mode with the remote control,
PRESS MENU
4725 OR 1267 OR 1461 (there are 3 different software versions, only one code
will work)
Service Menu will appear, Select PIC ADJUST and enter with VOL+
A second service menu will appear, the bottom adjustment in the menu is Back
Light setting and will be set to 100.
From the Mode Heading select CINEMA mode.
Select Back Light and reduce the setting to 59.
To memorise and exit Service Mode press Standby.
Model: Hitachi 37LD6600, 37LD6600A LCD TV
Symptom: No sound or intermittent sound
Repair/Solution:
Pins of headphone socket touching the chassis. Trim these pins and problem
solved.
Model: Hitachi L32A01, L32A01A, L32H01E, L32H01EA, L32H01U,
L32H01UA, 32LD8D20E_EA, 32LD8D20U, 32LD8D20UA LCD TV
Symptom: Audio is distorted constantly and may have some background noise
Repair/Solution:
Replace D845 and D846 (both UF5402 3A/200V 150A, part number:
VS30009366) on the power supply board (PSU).
Model: Hitachi 26LD6200 LCD TV
Symptom: Audio noise may be heard from speakers when unit is in Tuner
mode and the volume control is set to near minimum.
Repair/Solution:
Add four SMD jumpers on the Amp board to positions J100, J101, J102 and
J103 (JUMPER SMD 0603 R).
Model/s: Hitachi 26LD6600 & 26LD6600A, 32LD6600_A_B_C,
37LD6600 LCD TV
Tip: Burn in Mode when replacing Main PCB
When replacing the main PCB on these models, the new part may be in the
'burn in' mode from manufacture. This will result in the image on screen
flashing different colours.
To exit the burn in mode:
Use the remote control:
1. Press menu button
2. Press the following button sequence: 4,7,2,5:
3. Go to “OPTIONS” and then set “BURN IN MODE” to either ON or OFF.
Model: Hitachi 22LD4200 LCD TV
Symptom: Green horizontal line flashing across the screen intermittently.
Repair/Solution:
Remove resistor R149 on the Input signal board (Signal processing-analogue)
and replace it with Jumper SMD (0 ohm, part number: VS30001734).
Model/s: Hitachi 26LD6600 & 26LD6600A_B_C_D, 37LD6600,
37LD6600A, 37LD8600, 37LD8700C, 37LD8700U LCD TV
Tip: Hotel Mode
To enter the hotel mode of these model LCD TV:
1. Press Menu
2. Press the following buttons in sequence: 1,3,2,5
Model: Hitachi 28LD5200E LCD TV
Symptom: Intermittent Color or no color.
- Colour drops out after the unit has been running for two to three hours.
Repair/Solution:
Resolder capacitor C510 and other components in its vicinity.
Model: Hitachi 26LD6600 & 26LD6600A, 32LD6600_A_B_C LCD TV
Symptom: No sound/audio.
Cause: Sound setting may have been lost in the memory and defaulted to zero.
Repair/Solution:
Reinstate sound settings as follows:
Enter Service mode.
Press Menu then 4,7,2,5.
Go to Audio menu.
Select Sound 2 and enter the following values:
FM PRESCALER 15
NICAM PRESCALE AVL ON 35
SCART PRESCALE AVL ON 14
SCART VOLUME AVL ON 122
GO TO STANDBY TO MEMORISE SETTINGS
Model: Hitachi 22LD4500U, 22LD4500UK LCD TV
Symptom: No sound or very low sound on terrestrial and no sound on Digital
or any AV inputs.
Repair/Solution:
This is a software/firmware problem. Replace memory IC302 Type 24LC16
(part number: VS20167612). All customer controls are set to minimum on the
new IC. Please reset language and all picture controls to normal after replacing
the IC.
Model/s: Hitachi L32VP03E, L32VP03U LCD TV
Symptom: No switch on from standby mode.
If the TV is switched into standby when it has been running for some time and
is warm, it will not come out of standby until the set has cooled completely.
Repair/Solution:
Replace the crystal X104 (XTAL 14.318MHZ 20PF 20PPM SMD ROHS, part
number: VS30054926) on the main pcb/main logic board, the system control
section.
Model/s: Hitachi 32LD6200_A_B_C, 32LD6600_A_B_C LCD TV
Symptom: Picture Display Problem.
Cause: Various picture problems can be caused by poor connection of the
LVDS cable on connector PL103 on the Main board.
Repair/Solution:
Remove LVDS cable from connector PL103 and reinsert carefully.
Make sure both end of the LVDS cable are inserted properly between PL103
and the display panel.
Model/s: Hitachi 26LD6600 & 26LD6600A_B_C_D, 32LD8A10,
37LD6600, 37LD6600A & 37LD8500, 37LD8550, 37LD8600, 37LD8700C,
37LD8700CA, 37LD8700U, 37LD8700UA, 37LD8A20, 37LD8D10,
37LD8D20E, 37LD8D20U LCD TV
Symptom: Poor image quality or solarisation of image.
As shown in the images below.
This phenomenon may be intermittently and only displayed after a number of
hours/days.
Cause: The glue on the LDVS cable heats up over time and the properties
change and creating a contact problem within the cable and the PCB. This
causes permanent or intermittent picture problems
Repair/Solution:
Remove the LDVS cable and clean the connections at the LCD control panel. If
this step still not solves the problem, then replace the LVDS cable.
1) Part: VS30044366 CABLE 30P/130 QDIA UL20276
Reference:
LVDS
CABLE
LCD-PANEL<->PWB MAIN. To fit models:
26LD6600, 26LD6600B, 26LD6600C, 26LD6R10,
32LD8700CB, 32LD8700UB
2) Part: VS30044576 CABLE 30P/150 LVDS+FER UL20276
Reference:
LVDS
CABLE
LCD-PANEL<->PWB MAIN. To fit models:
(26LD6600A, 32LD6600, 32LD6600A)
3) Part: VS30044866 CABLE 30P/150 LVDS 32CMOB1
Reference: LVDS
PL103 <-> SCREEN V320B1-L01. To fit models :
32LD6600B, 32LD8A10, 32LD8600, 32LD8700C,
32LD8700TU, 32LD8700U
4) Part: VS30042003 CABLE CONNECTOR LVDS 30P/230
Reference: LVDS
CONNECTOR MAIN <-> PANEL. To fit models :
32LD6600C, 37LD6600, 37LD6600A, 37LD8600
5) Part: VS30053003 CABLE LVDS 30P/150 W/DC+F UL20
Reference: LVDS
CONNECTOR MAIN <-> PANEL. To fit model:
26LD6600D
6) Part: VS30051803 CABLE LVDS 30P/180 32CMOB1
Reference: LVDS
ÄPL103 <-> SCREEN V320B1-L04. To fit models:
32LD8A10A, 32LD8600A, 32LD8700CA,
32LD8700TU, 32LD8700UA
7) Part: VS30054878 CABLE LVDS 30P/130 UL20276
Reference:
LVDS
CABLE
To fit model : 32LD8600B
8) Part: VS30048584 CABLE LVDS 30P/230
Reference:
LVDS
CABLE
To fit models : 37LD8A20, 37LD8D10,
37LD8D20E, 37LD8D20U, 37LD8500, 37LD8550,
37LD8600, 37LD8700C, 37LD8700U
9) Part: VS30051781 CABLE LVDS 41P/230 37"HIT
Reference: LVDS To fit models: 37LD8700CA_UA, 37LD8600A.
Model: Hitachi 32LD6600 LCD TV
Symptom: Solarisation of the image.
Repair/Solution:
Replace X600, 6MHz Crystal (P/N: VS30006662) on signal processinganalogue
section.
Model: Hyundai Imagequest HQL260WR LCD TV
Symptom: Shuts down after a few minutes
Three 1000uf electronic capacitors in PSU replaced unsuccessfully.
Repair/Solution:
Change opto-coupler IC PC102-2. The problem solved.
Model: Hyundai Imagequest HQL260WR LCD TV
Symptom: Slow start-up problem.
Repair/Solution:
Replace the capacitor C109, C110 and C111 (all 1000uf/35v). Also check SMD
resistor R56 and R57 (both 22K) for dry joints.
Model: JVC LT32DX7B LCD TV
Symptom: No functions after lightning strike.
Repair/Solution:
The primary voltage 300v is present. But secondary voltage output was only 21
volt. Replace standby transformer T9201.
Model: KONKA LC42AS28 LCD TV
Symptom: Display show “No Input Signal” message only.
Try call out the OSD Menu, but it is response slowly about after 1 minutes then
the OSD came out. Even try other signal input like AV also same problem, but
when input the YPbPr signal, it can show the display properly. But their
responses to call out the OSD Menu still the same, slowly to come out.
Repair/Solution:
Since the signal YPbPr display ok but the AV and TV show error message “No
Signal Input”, so problem will be the Video/Audio processor N401
(TDA15063HI) or their corresponding components failure. Testing the voltage
supply pin 84 (Vcc=8V normal value), it only show = 0V! Check the Vcc
supply line corresponding components and found R811 open. After replaced
this R811 resistor, the TV was back to normal now. Even the OSD Menu also
working properly. That’s mean the N401 not working will affect the N400
(24C16) to Read/Writer data and cause it to slowly came out OSD Menu.
Model: Konka LC-TM3719 LCD TV
Symptom: After power on the TV, but it is stuck in standby mode.
Try using the remote control and the TV front panel button also not function.
The power LED still show the red colour light only.
Repair/Solution:
After replaced and program the N502 (24LC32) and the N405 (W39L040
AP70Z), the TV is working properly now
Collection Of LCD TV Repair Cases
PART 9
Model: LG 27LC2R Chassis LP61A LCD TV
Symptom: No backlight.
Repair/Solution:
Check the SMD fuse F1 on inverter board for open circuit.
Model: LG 32LC56 LCD TV
Symptom: Picture divided into several parts. Display distortion.
Repair/Solution:
Replace T-CON board (Part Number: 218394).
Model: LG 32LC56ZC LCD TV
Symptom: No start-up. Standby LED flashes from red to green.
Repair/Solution:
Replace the C202, C206, C217 and C218 (2200uf/10v all), and C226
(470uf/25v).
Model: LG 32LE2RZJ Chassis LP61A LCD TV
Symptom: Remotes control no functions at all.
Repair/Solution:
Replace SMD capacitor at output of IR receiver.
Model: LG 37LE2R Chassis LP61A LCD TV
Symptom: No start-up.
Repair/Solution:
Replace SMD regulator TL431 (U130) in PSU.
Model: LG 32LC45 LCD TV
Symptom: "No Signal" displayed. No sound and no picture. Backlight and
OSD menu is ok. LED is green color light.
Repair/Solution:
Try to update firmware if not then replace main signal board.
Model: LG 47LY95 Chassis LD75A LCD TV
Symptom: Negative picture and no sound.
Voltage output low at pin 7 of connector P202.
Repair/Solution:
Check Q202 (AP72T02GH), U203 (APU3037M), Q203 (AP60T03GH) and
connector P202 in PSU. Also check or replace C221, C222, C223 and C232.
Model: LG 47LF66 LCD TV
Symptom: No power
Repair/Solution:
Change the C202, C206 and C217 (all 2200uf/10v) on IP board (Inverter Power
Supply Board).
Model: LG 37LF66 LCD TV
Symptom: No power
IC U500 (ICE3B1565J) is short circuit and fusible resistor FB501 (2.2R) open
circuit.
Repair/Solution:
Check safety resistor for open circuit. Replace D501 (UF4007), 3.6v zener
diode ZD502 (1N5227) and C508 (33uF/50v).
Model: LG 32LC56ZC LCD TV
Symptom: No start-up. Standby LED flashes from red to green
Repair/Solution:
Check or replace C202, C206, C217, C218 (all 2200uF/10v) and C226
(470uF/25v).
Model: LG 32LC56 LCD TV
Symptom: Picture divided into several parts. Distorted picture
Repair/Solution:
Replace T-CON (Part Number: 218394).
Model: LG 32LC56ZC LCD TV
Symptom: Stuck in standby mode.
Repair/Solution:
Check & change C204. If the pcb board discolored around R208 resistor then
replace PSU.
Model: Logik LCXW32HDI LCD TV
Symptom: No sound or picture. The front controls light up & relay clicks.
Repair/Solution:
Check or replace R65 (2M) around U3 PSU for open circuit.
Model: Panasonic TX-32LED7FM LCD TV
Symptom: Dead.
Repair/Solution:
Replace the resistor R850 (820K/0.25W).
Model: Panasonic TX-32LED7FM Chassis GLP22M LCD TV
Symptom: Enter Service Mode.
Repair/Solution:
1. Press F button to access volume setting.
2. Press V- button on set until volume reaches minimum.
3. While still holding V- button press 0 button three times on remote control.
4. Press 1 and 2 buttons to scroll through the menu.
5. Press 3 and 4 buttons to select an adjustment.
62) Model: Panasonic TC32LX85 LCD TV
Symptom: TV does not respond from remote control signal
Cause: Leaky lines filter FL4036.
Repair/Solution:
Replace FL4036 (Part#: JOHAYY000011).
Model: Panasonic TC-32LX600 LCD TV
Symptom: Colour distorted with patches around object, sometimes happened
after running for 4 hours.
Cause: Digital signal processing error
Repair/Solution:
Try to reflow or replace IC4001.
Model: Panasonic TC-26LX85 & TC-32LX85 LCD TV
Symptom: Sound distortions, mostly noticeable during commercial
programming
Cause: Some stations send out of the specs signal causing sound distortion in
higher frequencies.
Repair/Solution:
Software upgrade is needed if unit has serial number before specified below:
**82330746 for TC26LX85
**82340342 for TC32LX85
Perform the upgrade following below steps:
1. Turn on TV and insert SD card into SD card slot.
2. Using remote control‘s left/right arrow button, select YES to start the
download.
3. When upgrade was completed, the screen will change
4. Unplug the TV from AC line and plug it back after several seconds. Power on
the TV and it is back to normal now.
Model: Philips 32PF3320/10 Chassis LC4.5 EAA LCD TV
Symptom: "F" is displayed on screen
Repair/Solution:
TV is in factory mode. To quit the factory mode, press both "VOLUME" "-"
keys and "PROGRAM" "-" for 5 seconds simultaneously.
Model: Philips Chassis BJ3.0E LA LCD TV
Symptom: Switches off for a second or two intermittently. Relay clicks and
standby LED remains green. When the TV switches off intermittently with
green LED lit, TV wills no sound or no picture.
Repair/Solution:
Please check the 27MHz KDS quartz crystal (SSB, item 1H00). If all yellow
marked crystals bearing with a "5E", "5J" or "5K" batch number just direct
replaced it. Also replace all the silver marked crystals bearing with a "6D" batch
number.
Model: Philips 42PF7621/D10 LCD TV
Symptom: High pitched noise coming from LCD power supply
Repair/Solution:
Check or replace 5025, 5026 and 5027 on LCD power supply and glue them if
necessary.
Model: Philips 23MW9010/37 LCD TV
Symptom: No sound.
Repair/Solution:
Defective sound output IC7731 (AN7522).
Model: Philips 23PF9966/37 LCD TV
Symptom: Picture jitter if contrast function is used.
Repair/Solution:
Replace transistor 7563 on Scalar mainboard.
Model: Philips 42PF7621/D10 LCD TV
Symptom: Stuck in standby. TV switches to protection mode. Green LED
flashes.
Repair/Solution:
Replace capacitors 2540 and 2544 (both 10nF). Change to both with 220nF.
Model: Philips Chassis BJ3.0E_LA LCD TV
Symptom: Switches off for a second or two intermittently.
Relay clicks and standby LED remains green. TV switches off intermittently
with green LED on, no sound or picture.
Repair/Solution:
Check 27MHz KDS quartz crystal (SSB, item 1H00). Replace all yellow
marked crystals (made in China) bearing a "5E", "5J" or "5K" batch number.
Also replace all silver marked crystals (made in Taiwan) bearing a "6D" batch
number. Note: Replace crystals with order code 242254301397.
Model: Polaroid FLM3232 LCD TV
Symptom: No startup.
Repair/Solution:
Replace Z9 zener diode with NTEPN4990 in the PSU.
Model: Samsung LE27T51B LCD TV
Symptom: Dark frame with color stripes.
Repair/Solution:
Its looks like the unstable voltage problem. Check and replace UP4 (L1117DG)
on T-CON board.
Model: Samsung LE32R73BD LCD TV
Symptom: No picture and no OSD menu. Backlight ok.
Repair/Solution:
Reflow LVDS socket on screen driver PCB and mainboard PCB.
Model: Samsung LE32R74BD LCD TV
Symptom: TV dead. Pulsating noise came from PSU and LED light flashes.
Repair/Solution:
Check schottky diode DM854 (MBRF1545CT) in PSU for short circuit.
Model: Samsung LN32A330J1DXZA, LN32A330J1NXZA LCD TV
Symptom: The TV takes longer to power on than normal.
The TV takes longer to power on than normal. You may hear several clicks
while the TV attempts to power on.
Cause: The electrolytic in the capacitors on the power supply board over time
will dry out causing the power supply to shut down during its initial power on
cycle.
Repair/Solution:
Refer to the capacitor cross reference guide below for the list of the capacitors
that should be replaced.
Model/s: Samsung LN40A650A1FXZA, LN46A650A1FXZA,
LN40A750R1FXZC, LN46A750R1FXZA, LN40A750R1FXZA LCD TV
Symptom: Unit tries to start with melody but cycles off and back on.
Repair/Solution:
If the unit tries to turn on and makes the start-up melody but then immediately
shuts off and starts again, unplug the LVDS cable and apply power again. If the
set stays on, replace the T-Con board.
Model/s: Samsung LNT3242HX/XAA, LNS2651DX/XAA LCD TV
Symptom: Picture is lost; sound OK after MAIN PCB was replaced
Repair/Solutions:
If you get the symptoms after replacing MAIN PCB and made all correct setups
in "OPTION BYTE":
- Lost picture after 5-10 minutes but sound OK, picture comes back if you
restart the TV but just to be lost again after the same interval or
- Picture is lost intermittently every 10-20 sec. and comes back itself, again
sound OK.
You may not have to come back with another Main PCB, this may be corrected
just by moving the connection between inverter and SMPS on the SMPS
board. If it was on A-CNM803 move it to S-CNM802 or vice versa from S-CNM802 to A-CNM803 on the SMPS board. If this is not working then use a
new MAIN PCB. This may be applied to other LCD models too.
Model: Samsung LNS4041DX/XAA LCD TV
Symptom: Unit Continually Cycling On and Off. Set turns on and off in a
continuous cycle. Play the melody each time.
Repair/Solutions: First, check the power supply voltages, if missing, replace
the power PCB. Next unplug the lvds cable. If the set continues to cycle,
replace the main pcb. If the cycling stops, replace the lcd panel. Part numbers
are version dependent, so be sure to check the set's version.
Model: Samsung LNS4051DX/XAA LCD TV
Symptom: Clicking repeatedly TV will not turn on
Cure/Solutions:
Found 2 electrolytic 100uf at 16v capacitors on the 5v line C115 and C123 bad.
Or replace the power supply.
Model: Samsung LNS4051DX/XAA LCD TV
Symptom: Dead Backlight Flashes On then Off.
Repair/Solution:
UNIT WOULD FLASH ON THEN OFF AND AUDIO WOULD WORK.
YOU COULD SEE VIDEO WITH A FLASHLIGHT. SOMETIMES UNIT
WOULD STAY ON AND RUN IF YOU CYCLED ON AND OFF MANY
TIMES. FOUND BAD SOLDER CONNECTION ON IP BOARD TI801 ON
PRIMARY SIDE. RESOLDERED AND CORRECTED PROBLEM.
Model: Samsung LNS4692DX/XAA LCD TV
Symptom: No video TV but has backlight and audio. TV will not come on.
Repair/Solution:
Found pico fuse open at cp1 on the T-CON PCB. If shorted CP1 with a wire
jumper, TV comes on and runs fine. Replace the Pico fuse or T-CON PCB.
Model/s: Samsung LNT3242HX/XAA, LNT3232HX/XAA LCD TV
Symptom: Can’t power on.
Repair/Solution:
TV would not come on. Removed the back and as soon as we did the set came
on. Found glue was around cables on the smps. Cleaned glue off and cleaned
the terminals. Set operates normally.
Model: Samsung LNT3253HX/XAA LCD TV
Symptom: After a few minutes when TV warms-up picture becomes distorted
Repair/Solution:
10-15 minutes after you turned on the unit panel warms-up and picture becomes
distorted. If you just push the TV's frame picture becomes even more distorted.
On the back of the panel the CONTROL ASIC area is very hot. Replace the
panel to fix the problem.
Model/s: Samsung LNT4065FX/XAA, LNT4665FX/XAA,
LNT5265FX/XAA, LNT4061FX/XAA, LNT4661FX/XAA LCD TV
Symptom: Blue screen without signal. If provide with signal the blue screen
will flash white short horizontal lines.
Repair/Solution:
Refit or replace LVDS cable, check if the cable not strangled by the metal cover
and loosen up the screws of the cover.
Collection Of LCD TV Repair Cases
PART 10
Model: Samsung LNT4665FX/XAA LCD TV
Symptom: Brightness lost after replaced MAIN PCB.
Repair/Solution:
Because MAIN PCB BN94-01199E is designed to work with both models
LNT4665FX/XAA and LNT4661FX/XAA when you replaced the board is
possible to lost the brightness. Go in SERVICE MODE and turn value LVDS
BYTE from 8 to 10.
Model/s: Samsung LNT5271FX/XAA, LNT4671FX/XAA LCD TV
Symptom: TV is cycling, the red LED light blinking and the relay is cycling
sometime TV will come on.
Repair/Solution:
TV is cycling, the red LED light blinking and the relay is cycling sometime TV
will come on. Even the Main board replaced, did not fix. This was a used unit,
found cable from the main board to the side AV jack was reversed, is not
labelled as to direction of use. This cable if reversed will be hot to the touch.
Found by removing and re-plugging and changing direction of cable TV worked.
This was tried on both model numbers with the same result.
Model/s: Samsung
LN32B360C5DXZA,LN32B530P7FXZA,LN32B650T1FXZA,LN32B 460B2D
XZA,LN32B540P8DXZA,LN32B550K1FXZA,
LN32B640R3FXZA,LN32B457C6HXZA,LN32B450C4HXZA,LN37B 457C6
HXZA,LN37B530P7FXZA,LN37B650T1FXZA,
LN37B550K1FXZA,LN40B457C6HXZA,LN40B550K1HXZA,LN40B 500P3F
XZA,LN40B550K1FXZA,LN40B650T1FXZA,
LN40B530P7FXZA,LN40B530P7NXZA,LN40B750U1FXZA,LN40B 540P8F
XZA,LN40B610A5FXZA,LN40B630N1FXZA,
LN40B640R3FXZA,LN46B650T1FXZA,LN46B530P7NXZA,LN46B 530P7F
XZA,LN46B550K1FXZA,LN46B610A5FXZA,
LN46B540P8FXZA,LN46B630N1FXZA,LN46B640R3FXZA,LN46B 750U1F
XZA,LN52B550K1HXZA,LN52B610A5FXZA,
LN52B550K1FXZA,LN52B540P8FXZA,LN52B530P7FXZA,LN52B 630N1F
XZA,LN52B750U1FXZA,LN55B640R3FXZA,LN55B650T1FXZA LCD TV
Symptom: Firmware blinking in Red at the top of the screen
Repair/Solution: Problem - After changing the main board, I'm now stuck with
the firmware blinking in RED print at the top of the screen.
Solution: The unit is stuck in aging mode. To exit, simply hit the menu button
on the TV itself.
Model/s: Samsung
LN32B360C5DXZA,LN32B530P7FXZA,LN32B460B2DXZA,LN32B 540P8D
XZA,LN32B550K1FXZA,LN37B530P7FXZA,
LN37B550K1FXZA,LN40B550K1FXZA,LN40B530P7FXZA,LN40B 530P7N
XZA,LN40B530P7FXZC,LN40B540P8FXZA,
LN46B530P7NXZA,LN46B530P7FXZA,LN46B550K1FXZA,LN46B 540P8F
XZA
Symptom: Flickering on the screen intermittently
When the unit is connected via HDMI to a Scientific Atlanta cable set top box
set in by pass mode for resolutions 480p and 720p a flickering will occur.
Repair/Solution:
Change the cable box to a fixed resolution. OR have the customer install the
latest TV firmware which can be located on samsung.com.
Model/s: Samsung
LN46A550P3FXZA,LN46A650A1FXZA,LN46A530P1FXZA,LN46A 750R1F
XZA,LN46A860S2FXZA,LN46A950D1FXZA,
LN46A540P2FXZA,LN46A850S1FXZA,LN46A630M1FXZA,LN46A 580P6F
XZA,LN52A530P1FXZA,LN52A750R1FXZA,
LN52A650A1FXZA,LN52A550P3FXZA,LN52A630M1FXZA,LN52A 860S2F
XZA,LN52A850S1FXZA,LN52A540P2FXZA,
LN40A530P1FXZA,LN40A450C1DXZA,LN40A330J1DXZA,LN40A 550P3F
XZA,LN40A650A1FXZA,LN40A630M1FXZA,
LN40A540P2FXZA LCD TV
Symptom: Unit cycles on/off during start-up.
Repair/Solution:
If the unit tries to turn on but begins to cycle on and off before any video is
displayed and all of the SMPS voltages are good, disconnect the LVDS cable at
the T-Con board. If the set starts and the backlights come on, replace the T-Con
board. If the set does not start, disconnect the LVDS cable at the main board. If
the set starts, replace the LVDS cable. If the set still does not start-up, replace
the main board.
Model/s: Samsung
LN32A330J1DXZA,LN32A450C1DXZA,LN32A650A1FXZA,LN32A 550P3F
XZA,LN32A540P2DXZA,LN32A330J1NXZA,LN32A300J1DXZA,
LN40A530P1FXZA,LN40A450C1DXZA,LN40A750R1FXZA,LN40A 330J1D
XZA,LN40A550P3FXZA,LN40A540P2FXZA,LN40A500T1FXZA,
LN46A530P1FXZA,LN46A860S2FXZA,LN46A750R1FXZA,LN46A 550P3F
XZA,LN46A650A1FXZA,LN46A950D1FXZA,LN46A540P2FXZA,
LN46A500T1FXZA,LN46A850S1FXZA,LN46A630M1FXZA,LN46A 850S1F
XZX,LN46A580P6FXZA,LN52A530P1FXZA,LN52A750R1FXZA,
LN52A650A1FXZA,LN52A550P3FXZA,LN52A630M1FXZA,LN52A 860S2F
XZA,LN52A850S1FXZA,LN52A540P2FXZA,LN52A580P6FXZA
Symptom: Auto-shutdown on 2008 LCD TV’s.
Repair/Solution:
Upon inspections of 2008 LCD TV's we have found that the LVDS (ribbon
cable) can cause an auto shut down. Even if the LVDS cable doesn’t look
defective try changing it anyway and retest the TV. It is a good practice to carry
a few extra LVDS cables for such testing circumstances.
Model/s: Samsung
LN32B360C5DXZA,LN32B530P7FXZA,LN32B650T1FXZA,LN32B 460B2D
XZA,LN32B540P8DXZA,LN32B550K1FXZA,LN32B640R3FXZA,
LN32B457C6HXZA,LN32B450C4HXZA,LN32B540P8DUZA,LN32B 450C3
HXZA,LN32B460B2DUZA,LN32B360C5DUZA,LN32B550K1FUZA,
LN32B530P7FUZA,LN32B450C3HUZA,LN40B530P7FUZA,LN40B 550K1F
UZA,LN40B457C6HXZA,LN40B550K1HXZA,LN40B610A5FUZA,
LN40B640R3FUZA,LN40B650T1FUZA,LN40B630N1FUZA,LN40B 540P8F
UZA,LN40B500P3FXZA,LN40B550K1FXZA,LN40B650T1FXZA,
LN40B530P7FXZA,LN40B530P7NXZA,LN40B750U1FXZA,LN40B 540P8F
XZA,LN40B630N1FXZA,LN40B640R3FXZA,LN52B550K1HXZA,
LN52B610A5FXZA,LN52B550K1FXZA,LN52B540P8FXZA,LN52B 530P7F
XZA,LN52B630N1FXZA, LN52B750U1FXZA LCD TV
Symptom: Backlight Failure Testing.
Repair/Solution:
Backlight failures can be partial or full failure check the backlight supply
voltage (refer to service manual). If supply voltage is present, use a flashlight
behind the television and shine a light through the panel. If the video is working
you will see it.
Model: Samsung LNS4051DX/XAA LCD TV
Symptom: Dead backlight flashes on then off.
Repair/Solution:
Unit would flash on then off and audio would work. You could saw video with
a flashlight. Sometimes unit would stay on and run if you cycled on and off
many times. Found bad solder connection on IP board TI801 on primary side.
Re-soldered and problem solved.
Model/s: Samsung LNT4065FX/XAA, LNT4665FX/XAA,
LNT5265FX/XAA, LNT4061FX/XAA, LNT4661FX/XAA LCD TV
Symptom: Half screen is purple colour.
Repair/Solution:
Half screen is purple color. That’s mean LCD panel controller board is
defective. Panel needs to be replaced.
Model/s: Samsung
LNT4069FX/XAA,LNT4066FX/XAA,LNT4669FX/XAA,LNT3255HTX/XAA
,LNT375HAX/XAA,LNT4042HX/XAA,LNT325HAX/XAA,LNT405HAX/X
AA,LNT2353HTX/XAA,LNT3753HX/XAA,LNT2653HTX/XAA,LNT3242H
TX/XAA,LNT3253HTX/XAA,LNT4042HTX/XAA,LNT4053HTX/XAA,LNT
4071FX/XAA,LNT4671FX/XAA,LNT5271FX/XAA,LNT4642HX/XAA,LNT
466FX/XAA,LNT4065FX/XAA,LNT4665FX/XAA,LNT5265FX/XAA,LNT26
32HX/XAA,LNT2642HX/XAA,LNT2653HX/XAA,LNT3232HX/XAA,LNT3
242HX/XAA,LNT3253HX/XAA,LNT3732HX/XAA,LNT4032HX/XAA,LNT
4053HX/XAA,LNT4061FX/XAA,LNT4661FX/XAA LCD TV
Symptom: Intermittent LCD Video Troubleshooting.
Repair/Solution:
Troubleshooting intermittent video problems can be time consuming, but these
tips may help narrow down the cause of an intermittent video problem.
The very first thing to do is to make sure the customer does not have OSD.
They can verify this by just pressing Menu or Volume on their TV remote
control. If they do have OSD, then the problem is most likely in the source and
not the TV.
The next step when encountering an intermittent video problem is to find out if
the backlights are on when the set looses video. You can probably obtain this
information from the customer before you schedule the call. Ask if they noticed
if the screen is completely black or if it is lit up slightly when the video goes out.
They may be able to notice it better if they stand at an angle to the TV and turn
it on or off and see if there is any change in brightness.
If the backlights are out, you need to know if the set ever has video when they
turn it on, or does it go out after they have had the set on for a period of time. If
the set occasionally will not have backlights when it is first turned on, suspect the panel or power supply/IP board. If the set has video for a while and then
looses the backlights, suspect a power supply/IP board or main board. Typically
the panel will cause a no backlight at turn on, while the power supply and Main
Board will cause the backlights to go out after a period of time. If the set has
backlights when first turned on and the lights change their brightness in several
steps before quickly going out, suspect the IP board.
If the backlights are on when the set loses video after it has been on for a while,
most likely the LVDS cable is defective. If the set has backlights but no video
when it is first turned on, the T/Con or Main Board would probably be at fault.
Always check the simple things first, like a LVDS cable that is not plugged in
properly or a power connector to the panel being loose.
There are exceptions to every rule, but this generally should help with
narrowing down no video in LCD sets.
Model/s: Samsung LN32A450C1DXZA, LN32A450C1HXZA,
LN32A450C3HXZA, LN32A330J1DXZA, LN32A330J1NXZA LCD TV
Symptom: Video will intermittently turn mostly white.
White screen with a faint image of OSD and video is in the background. Video
will intermittently turn mostly white with the OSD barely visible in the
background. Even a black image or when the panel should not be showing any
video, it is white. I found that one of the sub-boards inside the panel, the boards
that the ribbon cable from the T-Con connect to, are not seated properly and the
larger SMD capacitors on the board are intermittently making contact with the
metal frame of the set, effectively creating a short to ground.
This is one of the panels that are mounted upside down, so the stand mounts just
below and behind the panel frame. Any slight pressure from the stand can cause
the frame to make contact. In many cases, the TV can be slightly flexed to make
this issue occur.
Here, just beside a T-Con ribbon cable, you can see that the sub-board is not
seated properly, and is in fact bowing towards the outer frame.
Model/s: Samsung LNS4695DX/XAA, LNS4696DX/XAA,
LNS4096DX/XAA, LNS4095DX/XAA LCD TV
Symptom: Poor or Intermittent Video.
Repair/Solution:
Check the LVDS cable where it connects to the panel interface board. Be sure
that the cable does not have any glue on it. On occasion, the glue can cause a
poor connection if it gets into the connector. Remove glue or replace the LVDS
cable with BN39-00726A.
Model/s: Samsung LN32A330J1DXZA, LN32A450C1DXZA,
LN32A550P3FXZA, LN32A540P2DXZA, LN32A330J1NXZA,
LN32A450C1HXZA, LN32A450C3HXZA,
LN32A300J1DXZA LCD TV
Symptom: Standby light is on, flashes once briefly then unit attempts to turn on
Repair/Solution:
If the unit will not turn on, but the red standby LED is on and flashes once
quickly when the power button is pressed on the remote or the TV, the 2200uf
10v filter capacitor on the SMPS has failed. This capacitor is located in the
upper right side of the power supply close to the cable that connects the main
board. Visual inspection will normally show that it has a swollen top. Replace
capacitor and inspect the others in the filter stage to restore operation.
Model/s: Samsung LNT4061FX/XAA, LN32A450C1DXZC,
LN32A550P3FXZC, LN32A550P3FXZX, LN32A450C1DXZX,
LN32A650A1FXZA, LN32A450C1XZD, LN32A450C1DXZA,
LN32A540P2DXZA, LN32A450C1XZP, LN32A550P3RXZD,
LN40A530P1FXZA, LN40A530P1FXZX, LN40A450C1HXZX,
LN40A450C1DXZA, LN40A750R1FXZA, LN40A450C1DXZX,
LN40A530P1FXZC, LN40A550P3FXZC, LN40A650A1FXZC,
LN40A550P3FXZX, LN40A750R1FXZC, LN40A330J1DXZX,
LN40A650A1FXZX, LN40A450C1XZD, LN40A450C1DXZC,
LN40A330J1DXZA, LN40A550P3FXZA, LN40A650A1FXZA,
LN40A750R1FXZX, LN40A550P3RXZD, LN40A330J1XZD,
LN40A630M1FXZA, LN40A540P2FXZA, LN40A650A2RXZD,
LN40A630M1FXZC, LN40A630M1FXZX, LN40A610A3RXZD,
LN40A500T1FXZA, LN40A330J1XZP, LN40A450C1XZP,
LN40A650A1RXZP, LN40A610A1RXZD, LN40A650A1FXZD LCD TV
Symptom: Troubleshooting Inverter PCB boards
Repair/Solution:
The inverter PCB is the power supply for the Cold Cathode Fluorescent tubes.
The inverter acts exactly like the ballast used in a standard fluorescent light
fixture. In the case of an LCD TV, 24 volts from the power supply is applied to
a switch mode power supply (SMPS). The SMPS outputs ~1000 Volts to
energize the bulbs then the voltage drops to ~ 500 volts for run operation. The
SMPS switching frequency is around 90 KHz.
The first step for verifying inverter board operation is to confirm the 24 volt
supply is present. An oscilloscope can also be used to verify the SMPS circuit is
oscillating. Simply holding the oscilloscope probe in the area of the switching
transformer will show screen activity if the switching action is taking place.
Measuring the SMPS output with standard equipment is not recommended as
this is high voltage and at a high frequency.
Model/s: Samsung LN40A650A1FXZA, LN46A650A1FXZA,
LN40A750R1FXZC, LN46A750R1FXZA, LN40A750R1FXZA LCD TV
Symptom: Unit tries to start with melody but cycles off and back on.
Repair/Solution:
If the unit tries to turn on and makes the start-up melody but then immediately
shuts off and starts again, unplug the LVDS cable and apply power again. If the
set stays on, replace the T-Con board.
Model/s: Samsung LNT4071FX/XAA, LNT4671FX/XAA,
LNT5271FX/XAA LCD TV
Symptom: Video Stuttering or Hesitation
Repair/Solution:
The customer may complain that the video has a stutter or hesitation when
viewing regular programming, either standard definition or high definition.
To fix, go into the customer menu, select Picture, then scroll to Auto Motion
Plus 120Hz and select Off.
This enhancement circuit works for some movies, but can introduce severe
hesitations and ghosting on regular programming. The customer should also be
informed that this does not affect the 120Hz operation of the panel. The panel
operates at 120Hz regardless of this setting.
Model/s: Samsung LN52A650A1FXZA, LN40A650A1FXZA,
LN46A650A1FXZA, LN52A650A1FXZC, LN46A650A1FXZC LCD TV
Symptom: Will not turn on, cycles on and off with start-up melody, no
backlights
Repair/Solution:
If the set will try to turn on and the start-up melody sounds but no backlight
appears and the set cycles off and on every 5 to 10 seconds, unplug the LVDS
cable from the T-Con/FRC board. If the set then runs and the backlights come
on and stay on, replace the defective T-Con/FRC board.
Model/s:
LNT4069FX/XAA,LNT4066FX/XAA,LNT4669FX/XAA,LNT4071FX/XAA,
LNT4671FX/XAA,LNT5271FX/XAA,LNT4065FX/XAA,LNT4665FX/XAA,
LNT5265FX/XAA,LNT4061FX/XAA,LNT4661FX/XAA
Symptom: Unit cycles on and off several times before starting.
Repair/Solution:
If the unit will cycle on and off several times before turning on and then playing
fine, check the power supply carefully for filter capacitors with bulged tops.
Replace the capacitors or power supply to correct the issue.
Model: Samsung 32 Inches LCD TV
Symptom: Hissing or Hum noise of the SMPS in 32 inches LCD TV
There may be a sort of hissing noise in the SMPS for 32" LCD TV. The noise
occurs when the set is in the stand by condition. The SMPS code is BN96-
03057A and defective SMPS version is the "REV 1.1".
Repair/Solution:
Replace the SMPS to new version (V1.2 or latest version).
Model: Samsung 26, 32 & 37 Inches LCD TV Year 2009 Europe models
Symptom: No Power, No picture or no backlight.
Cause: DP805 Diode (MUR360).
Repair/Solution:
Change DP805 from MUR360 to 31GF6 diode on IP boards.
=> MUR360 risk range: 0907*/0908*/0909* marked on diode.
1. Change MUR360 Diode to 31GF6 Diode
2. Marking a dot on yellow box after changing this diode.
Model/s: Samsung LN26B460B2DXZA; LN26B360C5DXZA;
LN26B457C6HXZA; LN32B460B2DXZA; LN32B360C5DXZA;
LN32B540P8DXZA; LN32B457C6HXZA; LN32B530P7FXZA;
LN32B550K1FXZA; LN37B530P7FXZA; LN37B550K1FXZA;
LN37B650T1FXZA
Symptom: No Backlight but sound ok.
TV will power up but have no backlight operation (No display). Sound is ok.
Procedure:
1. Verify that the TV is within the serial number range by checking the ninth
digit in the serial number (i.e. AZ4D3CTS5 Ninth digit is a 5).
2. If the digit is 4 or 5, check the number on the diode itself to verify whether it
has already been replaced.
3. If the diode has “0907”, “0908” or “0909” on its case (refer to photos 1 & 2),
replace with new (Part number 0402-001415).
Verify the cause of the symptom by measuring (in circuit) across the diode
(location DP805) (see photos 3 through 6). If the resistance measures between
500 and 600 ohms, the diode is good and therefore the symptom is being caused by a different reason. If the resistance measurement approaches zero ohms
(shorted) the diode is defective and needs to be replaced using part number
0402-001415.
Repair/Solution:
There are two versions of the IP board with different physical layouts (refer to
photo 7 and 8 for part location) using the same diode type. Replace the diode
using standard soldering methods for a lead-free application. If the diode is not
available, order the IP Board.
Model: Samsung LN32C350D1DXZA LCD TV
Symptom: Multiple Vertical lines.
Repair/Solution:
Try to call out the OSD Menu, the multiple vertical lines that do not go through
the OSD menu. If the symptom does not affect the OSD menu (as shown above)
or does not appear in the test picture, replace the mainboard only. Do not
replace the LVDS or T-Con board or the LCD Panel.
Model: Samsung LN-52A850 LCD TV
Symptom: The image breaks up or doubles images on the right side of the
screen.
Repair/Solution:
Replace T-CON board and problem solved.
Model: Samsung LN46B530P7NXZA LCD TV
Symptom: There is colour distortion on objects or people’s faces.
Repair/Solution:
The LVDS cable can cause this if it isn’t seated correctly. Check the position of
the LVDS cable and the contacts. If it is seated correctly, replace the LVDS
cable.
Model: Samsung LNT4661FX/XAA LCD TV
Symptom: Half of the screen is black or purple on all inputs.
Repair/Solution:
When call out the OSD menu, the problem also affects the OSD menu, replace
the LCD panel.
Model: Samsung LNT5271FX LCD TV
Symptom: Left side of the screen is dark. The right side of the screen have
horizontal lines with distorted video.
Repair/Solution:
The symptom also affects the OSD Menu, so replace the T-CON board then
problem solved.
Model: Sharp LC32P55E LCD TV
Symptom: Dead after start-up. Bang-noise was head before.
Repair/Solution:
Replace R751 (0.1R/2W), IC704, D762, D725 and C725 (470pF/3K) in PSU.
Model: Sharp LC32P55E LCD TV
Symptom: Red LED light appears for a seconds, relay clicks then dead.
Repair/Solution:
The resistor R751 was blown. Replace the IC704 & R751.
Model: SHARP LCD TV Repair tips
Symptom: The Sharp LCD TV still under protection mode?
The Sharp LCD TV always has the protection mode come out. Normally, the
repairer will first check the inverter board, after that power board (PSU), if still
can't get any result, and then they will check the signal board/mainboard. Even
you change the inverter or PSU board, the LCD TV still under protection mode.
Actually the LCD TV has been fixing by the repairer, but they don't know the
TV still remember the past protection mode inside the memory. So, now you
need to know how to clear this protection error inside the LCD TV memory.
Repair/Solution:
Press & hold the CHANNEL DOWN & VOLUME UP buttons, and then power
ON the LCD TV. The LCD TV Protection Error has been clear & solved the TV
problem.
Model: Sharp LC-52BD80U LCD TV
Symptom: Display has horizontal lines, White Display or Flashing/Flickering
picture.
Cause: LCD Driver PWB ribbon cables may be damaged.
Repair/Solution:
When servicing units due to an occurrence mentioned above, check and if
necessary replace the LCD Driver PWB ribbon cable.
Collection Of LCD TV Repair Cases
PART 11
Model: Skyworth 30AAA Chassis 8TP2 LCD TV
Symptom: Sometime display white screen and then back to normal. After
power on the TV, the words “Please wait” character move to top left side.
Repair/Solution:
Replaced the U804 (APX1117-5V) and the TV is working properly now.
Model: SONY KDL32S2010E Chassis WAX2 LCD TV
Symptom: Switches to standby for a short while, then back again.
Repair/Solution:
Replace standby push button on user control, has contact resistance.
Model: Sony KDL32U2000 Chassis SE1 LCD TV
Symptom: No Picture.
Repair/Solution:
Check SMD fuse CP101P on T-CON board. The T-CON board is behind the
BDT board
Model: SONY KDL40U2000 with SE1 Chassis LCD TV
Symptom: No start-up, red LED light flashes 3 times.
Repair/Solution:
TV has slow start-up before this symptom occurred. When check standby 5v ok
and PSU is heat sensitive. Check and replace the C6055 (47uf/25v) in G2
supply it will solve the problem.
Model: SONY KDL40U2000 LCD TV
Symptom: Error codes 4
LED light turns green, flashes 4 times then goes green again and flashes 4 times
again. Fuse (500mA) on inverter panel is open circuit.
Repair/Solution:
Replace the fuse on inverter board.
Model: SONY KLV26U2520 Chassis SE1 LCD TV
Symptom: No picture but sound ok.
Repair/Solution:
Check SMD fuse CP101P on LVDS panel (T-CON).
Model: Sony KDL32U2000 Chassis SE1 LCD TV
Symptom: Stuck in standby. Standby LED light is green.
Red LED light flashes 3 times. No remote control or front panel functions.
Repair/Solution:
Check or replace D301 zener diode (can be use a 5v zener diode) for short
circuit.
Model: Sylvania LC-420SSB (A81 H1UH)
Symptom: High frequency noise from power transformer T600 when the TV is
in the standby mode.
Repair/Solution:
Remove diode D655 from the power supply.
Model: Sylvania LC420SS8 LCD TV
With Power Supplies:
1ESA20888
1ESA20888-PW
1ESA14710
1ESA14710-PW
Symptom: Low level hums (buzz) sound from speakers.
Repair/Solution:
Perform the following fix on the power supply board.
1. Cut Jumper J220.
2. Cut Jumper J256.
3. Solder a wire (about 140mm AWG20) from J190 to J256. On J256, solder the
jumper on the Audio Amplifier (IC800) side.
Model: Toshiba 32WLT58 LCD TV
Symptom: Dead
Repair/Solution:
Check F870 (2A), Q860 (STRZ4479) and D866. If F801 open circuit, then
check the voltage regulator Q820 for short circuit. Also checked R831
(4.7R/5W) and D825 (MTZJ33A).
Model: Toshiba 20W330DB Chassis 17MB222 (Vestel) LCD TV
Symptom: No Power
Repair/Solution:
The main fuse F800 (T2.5A) blew. Found main filter TR801 short circuit, D824
(ST-TH12R06FP) also shorted. Check SMD IC802 (FAN7529) and Q803
(FQPF13N50C) both short circuits. R830 (0.22R/3W) and SMD resistor R823
(15R) both also open circuits.
Model: Toshiba 20W330DB Chassis 17MB222 (Vestel) LCD TV
Symptom: Stuck in Standby Mode.
Repair/Solution:
If the EEPROM IC was removed, the standby LED light turns to green colour.
But still can’t start-up. Try to programme a new EEPROM IC, because can’t get
the actual version of firmware, and then replace a new mainboard (17MB22-2).
The TV is working properly now.
Model: Viewsonic N3260W VS114361M LCD TV
Symptom: No startup
Repair/Solution:
Check capacitors (with ESR Capacitor tester), Q7 and SMD resistor R65 (5.1R)
in primary side of PSU. This TV set using the FSP228-3F01 PSU.
Model: Viewsonic N3260W VS114361M LCD TV
Symptom: Picture flickers and is brighter on the right, than on the left.
Repair/Solution:
Replace four electrolytic capacitors (2x 820uF and 2x 1000uF) in upper left
PSU.
Model: Vizio VO42LFHDTV10A LCD TV
Symptom: Green distortion in picture.
Repair/Solution:
If PSU secondary side voltages ok. Check & clean contacts of ribbon cables
coming from control board.
Model: Westinghouse LTV40W1HDC LCD TV
Symptom: Blue screen. No sound, no picture and no OSD.
Repair/Solution:
Replace circuit protector fuse on T-CON board.
Model: Wharfedale LCD3210AF Chassis 17MB116 LCD TV
Symptom: Starts-up, backlight came after that switches off immediately.
TV runs ok when inverter board is externally supplied with 24v.
Repair/Solution:
Replace the C877 and C878 (15nf/630v) between heatsink of switching
transistor and larger transformer on the primary side of the PSU.
No comments:
Post a Comment
Note: only a member of this blog may post a comment.