
This board is from a no-name RGB LED DMX PAR lamp (they're all over your favourite auction site and tat bazaars); it's rated at 12V 3A and joined the afterlife with a whomp. The IEC inlet contained a 1A fuse (vaporized), but the board also had a through-hole one, which was similarly toasted. There's no inrush limiting, nor mains EMI filtering. As a sidenote: the lamp unit has an IEC socket and a plug to allow for daisy-chaining, but the earth pins aren't linked, so it would be all fun and games if something down the chain wasn't all-plastic and needed a ground connection!
I plan to ultimately replace the board with a decent (anything would be better!) module but decided to repair this one just for the experience as I have most of the parts in stock. In the pic, the board is waiting for a new power FET and mains smoothing cap (it had a fake Nichicon). I have replaced one shorted 1N4007 and the others will be replaced too - note the lead thickness on the new diode (bottom) compared to the originals (tight-ass cheapies). The output caps will also be changed and I'll check/change the shunt reg and opto as necessary. The electrolytic cap top left is screen printed 10uF/50V, but the one originally fitted was rated at 25V (I've put in a new 63V one); out of curiosity, I'll measure the voltage across it once the board's working again. The PWM chip is a CR6853T.
At the moment I've put a link in the on-board fuse position, but considering there's already a fuse on the power socket, I'll replace it with a 10R power resistor. The original board had flyleads soldered on for AC in and DC out so I'll use the AC holes to mount some rudimentary filtering and a MOV.
Yeah, I know this one's not really worth repairing, but it was a case of 'challenge accepted'.
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