Skyworth LCD TV 42E65SE (8R68) motherboard repair examples - appliance repair - Huaqiang electronic network

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

MOS power IC full range

Photocoupler

The customer sent a Skyworth LCD TV 42E65SE to turn on the power machine. The green light is not able to be turned on twice, that is, no light and no sound. Disassemble the shell and measure the power supply. The backlight integrated board interface repeatedly presses the remote standby button. The BL terminal always has a voltage of 0V. Then measure the output voltage of the power board is normal, and then transfer to the motherboard to measure U24/3.3V output 3.38V U20/1.2V output 1.29V U18/1.8V output 1.79V U19/5.0V output 4.98V and measure on the motherboard Big chip RTD2692D (296 feet) power supply clock reset did not find suspicious, the initial judgment is basically normal, when the thinking is suddenly the machine backlight is lit, the speaker has the sound of the boot music. You can also watch the program by connecting the video signal. I thought this is not the main program and FLASH data problem is still on the motherboard (5800-A8R632-0P20) or RTD2692D virtual soldering, after the repair of the large chip after the repair, my heart is dark, continuous switching machine several times are normal, my heart Still not practical, or wait for the machine to cool for a while and try again, it was busy for about 2 hours, and then booted up as before, my heart was heavy, I had to move the oscilloscope to scan the LDO output voltage on the motherboard, when sweeping A burr was found at U24, and the burr was larger when the probe was moved to U20. This truth will be revealed, decisively replaced with U24 and U20 filter orange capacitor 100U/16V four (the orange capacitor quality is not very good, has replaced the high-quality blue capacitor 200U/16V), and then scan with the oscilloscope did not find The burrs are straight and straight. In turn, the U24 output is 3.28VU20 and the output voltage is 1.19V. Let the machine cool for 2-3 hours. The program can be played normally at any time. This motherboard is completely repaired. This is shared with everyone!