1, the power supply section - System 3.3Vstb
3.3Vstb standby 3.3V, converted from stand-by 5V, the standby is not controlled. PM power supply for the system, MbootFLASH power supply, power supply and other touch keys. This voltage is not normal will cause the machine does not start.
2, part of the system + 5V power supply ---
+ 5V system main 5V, stand-controlled design capacity? To 5A. For system + 2.5V_Normal, 33V_Normal, USB5V, 8G80 of nuclear power.
3, part of the power supply system --- 3.3V: 33V_Normal
3.3V system uses a dual layoutN5 and N4, the actual use of N5, namely AP1084-3.3V.The difference is not the same package, N5 temperature better, but the price is a little expensive.
4, the power part --- System 2.5V: + 2.5V_Normal
2.5V system for MST6i78 and 8G80-powered, stand-controlled.
5, the power part --- MST6i78 nuclear power: V the CC 1.2V
MST6i78 using nuclear power by 12V DC-DC converter and the size of about 1A. MST6i78 for the kernel. This voltage theoretical value of 1.26V, the actual design of the DC-DC is about 1.3V, the chip pin is about 1.27 ~ 1.28V.Noting chip pin voltage must be greater than 1.26V, below the words will cause the system to crash, reboot and other failures.
6, the power part --- LCD TCON supply: VCC-Panel
LCD TCON supply using the most commonly used MOS tube exchange circuit , switching power supply to achieve TCON control and input power options. If this part of the power output fault, such as U8 damage will cause the LCD screen has no output, the phenomenon manifested as black or gray screen (backlight time), or there is no sound in FIG.
7, the power part --- USB powered: 5V_USB1
8, the control section --- Standby control circuit: STANDBY
Standby control two-stage reverse way, when the power of the control pin PW_CTL MST6i78 default to a high impedance state so that the control terminal B V5 is high level , after two high reverse standby, power-up, output + 12V The system starts. After the system starts again based on EEPROM read control PM_CTL taken to the standby state, thereby controlling the whole organ is due to open state or standby state.
9, the control section --- backlight ON / OFF and dimming circuits
Adopt a common backlight control (BL-ON / OFF) circuit and a dimming circuit (BL-ADJUST). Dimming determined by the LCD screen, the DC dimming C1 bit 4.7uF; DC dimming system if C1 no welding , BL-ADJUST will cause voltage instability, resulting in the screen flashing fault. DC dimming voltage is too high or too low, dimming frequency and pulse width settings screen can also cause improper flashing, black and other failures.
10, the storage section --- MbootFLASH
mbootflash uses 32M of SPIflash, inside the storage system boot program and part of the system, the user data. System after power is directed through mboot first start, mboot complete system start and then start the main program (stored in NANDflash)
11, the storage section --- NANDFLASH
The main program is stored in the system in NANDFLASH, MST6i78 movement with a 1Gbit of NANDFLASH. Whether MBOOTflash or NANDFLASH, any fault will cause the machine can not start.
12, the storage section --- EEPROM
EEPROMN10 system, the main storage of plant data and user data; N13 is the HDMI HDCPEERPROM, using 24C04. EDID HDMI built-in to? The main program, namely NANDFLASH in.
13, the key circuit --- mechanical keys
Using mechanical buttons: XS8 to 3 the PIN ; R179, R180 to 2K2
14, remote control lighting and control circuits --- support, light
15, DDR circuit --- DDR3_H5TQ1G63BFR-12C
MST6i78 use of two 1Gbit DDR3, N15, N17. If DDR is faulty, causing the machine can not start back. By measuring the pin-by-pin impedance to determine whether the welding and other faults. Further work properly clk (R412, R413, R163, R164) DC level should be about 0.7V.
16, the interface section --- HDMI Interface
MST6i78 support 4? HDMI input, EDID using a built-in program mode. Meanwhile MST6i78 of ESD are strong, so close to the ESD HDMI interface devices do not need to mount. Lower right:
17, network interface chip interface section --- IP101A
6i78 integrates the MAC, but the need for an external PHY. The system uses the system as IP101A PHY interface chip, the power supply is 3.3V.
18, interface section --- HDTV and AV2 Interface
19, the interface section --- AV Interface
20, the interface section --- VGA Interface
Generic VGA interface circuits, and high-definition sound reuse. Note pin4 through VGA interface and can be programmed pin11 MBOOT, monitor print information.
22, coaxial output circuit interface section ---
23, headphone output circuit interface section ---
MST6i78 headphone output directly from the output pin, through LRC (L45, R597, C455) to achieve the filtering effect, without any amplification, direct output. Headphone detection circuit PMD_MT directly directly on mute circuit, mute headset hardware control after insertion.
24, switch mute circuit
Universal switch mute circuit, pay attention to the audio output of the AV mute control is realized by this circuit, namely MUTE_602.
25, digital circuit for discharge
The system uses a new type of I2S? Word for discharge, N14 / TSA5707.
26, tuner section --- 5V-IF
12V After 10R / 2W of resistance partial pressure to the N24, N24 generated by linear regulator 5V-IF power , as the power tuner.
27, tuner section --- tuner
Digital tunerU1.
30, LVDS portion 28, tuner --- tuner part in the pre-amp circuit
Due to insufficient magnification tuner, in order to compensate for the acoustic attenuation of the signal, the tuner IF output needs to be increased in a pre-amplifier circuit. This is typical of the transistor common-emitter amplifier.
This part of the circuit parameters V18 prone to drift caused under TV image is not normal, the sound affect the image signal smearing and other issues. You can change or replace V18 R412 experiment.
29, tuner circuit portion --- SAW
Acoustic problems will cause a corresponding image or sound is not normal, can directly replace the SAW. SAW models need to use this machine, and can not be replaced.
30, LVDS part
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