Different brands of products, because of different circuit structures, different designs, methods and steps for troubleshooting. Take Panasonic as an example: the SC board is the Y board, the SS board is the X board, the SU and SD are the upper cache board and the lower cache board, and the C board is the selection board. The SC, SU, and SD boards are located on the left side of the screen (rear view), the SS board is located on the right side of the screen, and the C board is located on the lower edge of the screen. The output of the SC board is added to the SU and SD boards, and the SU board and the SD board are directly connected to the screen to drive the screen. The SU board is responsible for the scanning of the upper half screen, and the SD board is responsible for the scanning of the lower half screen. The SC board generates an AC voltage that illuminates the drive screen. The period of this AC voltage is 5 US. The amplitude is 180VP-P. The discharge AC voltage output by the SC board is simultaneously applied to the SU and SD boards, and the SU and SD boards are applied to the screen by the timing pulse sent from the logic board. Panasonic PDP TV protection circuit design is very perfect, fault self-diagnosis function, using the number of red flashing on the panel to indicate the faulty board and circuit unit. The lamp flashes 7 times, indicating that the fault is abnormal in the SU, SD, and SC boards. The lamp flashes 6 times, indicating the energy recovery circuit that is faulty in the SC board. The light flashes 8 times to indicate the fault on the SS board. If the screen is broken, it will also cause damage to the SU and SD boards. At this time, you need to remove the screen. Under bright light, you can see black spots on a certain pixel. Phone Accessories,Smartphone Holder,Cell Phone Stand Holder,Adjustable Stand Holder Shaoxing Shangyu Kenuo Photographic Equipment Factory , https://www.kernelphoto.com
The following power supply voltages are common on SC boards:
VSUS: 180V. VSET: 320V VAD: -90V. VSCN: 145V.
The following voltage is on the SS board: VSUS: 180V VDA: 65V VE: 140V
Because the manufacturer constantly improves the parameters of the screen to improve the lighting effect and save power, the above voltages are quite different on different screens. The service manual is subject to change.
Both the SC and SS boards have energy recovery capacitors. If the circuit is working properly, the voltage on this capacitor should be equal to half the VSUS voltage: 90V. If this voltage deviates from this value, it means that the board is not working properly.
There is an LED on the SC and SS boards. If the LED is normally illuminated, the board is working normally. The most common fault of the SU and SD boards is the breakdown of the driver IC connected to the screen. Just use the first test to find out. If the SC and SD boards are slightly abnormal, they often cause colored shifts on the screen, the image is greenish, the image is beating, and the image is dark. If the SU, SD board and the screen cable are not crimped properly, there will be horizontal horizontal lines and horizontal bands on the screen.
The C board is connected to the data electrode of the screen, and the data electrode of the driving screen operates. There is VDA voltage on the C board: 65V, 5V power supply. The C board works abnormally. Vertical vertical black bands often appear. The cable at the bottom edge of the screen contains a soft-packaged IC. If the IC is bad, it will cause a vertical black line or a vertical black band. Just use a magnifying glass to carefully check whether the soft-packaged IC case inside the data cable is bulging or cracking, and you can judge whether the screen is faulty.