I have 5 repairs in this town, and I don’t have to go to the door to wait for the rice cooker to be repaired.
These were thunderstorms, and some LCD TVs were repaired at home. Talk about this Skyworth 37-inch, open the back cover, power board model: 5800-P42TLQ-0000, preliminary view of the sub-power IC split, sampling TL431 and a triode blasted. I am familiar with this power board. It has a 5V power supply for the CPU, and a controlled power supply of 24V and 12V. There are PFC circuits and high-voltage backlight circuits. There is no patch component except the two backlight-driven small boards. Really good material for entry level. There is no short circuit at each output end of the power supply. First remove the power supply board, connect the backup power supply board, and light a backlight to find out the damage of the main board.
Since the motherboard is in good condition, talk about the repair price and pick up the power board for maintenance.
Digital meter voltage capacity large capacitor has no residual power, diode gear is measured in the road, the insurance is intact, the power tubes are not broken down, the power output terminal diode is not short-circuited, only the two diodes supplied by the sub-power supply break down, replace them and obviously damage Components NCP1014, TL431, C1885, and suspicious component optocoupler, etc., the fuse end is connected to the 100W bulb, soldered to the power plug, powered test machine, or no 5V output, carefully check the sub-power supply related circuit, no abnormality, then change one Only NCP1014 test machine, still no 5V output, suspected that the small transformer is broken, take it out is really it, there is no ready-made accessories, look for the transformer from the satellite receiver power board, deliberately require the primary IC power supply is greater than 12V, found one, is Q100 drive of. Comparing the two-pin transformer pins, the installation, only the secondary output position problem needs to be changed. Powered 5V, and connected PR-ON/OFF to 5V, 24V, 12V, and access to the dummy load test machine.
The Skyworth 5800-I42TLQ-0000 power supply board is struck by lightning. The small board 5800-I42TLQ-1000 must be taken down and waiting for replacement. After removing it, it can measure the quality of four power tubes. In addition, the small board 5800-I42TLQ-0010 is controlled. After the two small transformers, in a primary parallel indicator light (two small LEDs in reverse and parallel and then string 2K or so of resistance), easy to observe, power supply board, BL-ON / OFF connected 5V, indicator light Can be lit for 1 second and then extinguished, indicating that the control panel 5800-I42TLQ-0010 is good, but the reverse is broken. After replacing the drive plate and other damaged components, connect the 40W incandescent bulb to the primary of the high voltage transformer, and use the same method to check whether the backlight is repaired.
Repair this board really does not need drawings, PFC circuit is easy to break NCP1653 and power tube, do not care about it when there is no spare parts.
Home installation, beautiful debut Skyworth 168P-P42TLQ-00_LCD color TV power supply drawings.pdf
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