Need help with exploding drivers!

I got these drivers from banggood after seeing comftychairs project for his car. I decided to do the same thing. The first mod went great. But when I did the next two the mcu blew up when I connected power. In the first pic I had it connected to the Led, and second with no Led. I double checked polarity before connecting, and didnt do anything different from the first one which is still working. Any ideas what I did wrong?

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https://www.flickr.com/photos/krisandalex/15000681738/player/

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Dunno, I've only used two of that same version so far (only had two, have 10 more in transit) and they both did fine with no special tricks. All the others I've built used the larger LM2596 converters, but at the light levels needed for car stuff the little boards are able to output enough without going into their strobe-like protection mode. I use the big boards for trunk lights where there's plenty of room, and save the little boards for where it all has to fit in the stock dome lamp housing.

What was the input voltage? They are safe to power up with no load attached, I do that to set the voltage adjustment to the minimum before installing.

I had the car off, input was only 12.6v, it pop as soon as I plugged them in. I might order some more and test them with a power supply before I install them.

What car? Do you have a wiring diagram for the domelamp? Most of them are simple in theory, but when it comes to tracing out the pins and what goes where it can get tricky. My Honda was easy, everything readily apparent. But the Camry had most of the conductors hidden, molded inside the housing and going seemingly every which way but where you'd assume they went.

Unless there was a defect on the boards before you started, the only thing I know of that can damage them is reverse polarity... these have NO protection of any kind for that.

The car is a 2013 Nissan Versa, but the wiring is a no brainer. I solder the wires on to the backside of the light socket. I’m sure I missed something, I was doing this all at 3am. Going to order a few more from Ebay, they’re a little cheaper.

One end of the bulb constant +12v, other end grounded by either the door pins or the override switch? Does it have the typical import 'DOOR/OFF/ON' slider switch on the domelamp itself?

On mine I cut out the entire middle of the housing and attached the driver's inputs direct to the switch terminals, so the stock bulb holder was no longer present.

I can’t attach it to the switch terminals, the switch itself has brass pins that slide back and forth to make contact with the traces. Maybe I got the polarity wrong, it was late and I was tired. I will triple check later.

That's the Honda, I don't think I kept pics of the Toyota (I should have, it took a lot more fiddling). The switch contacts are on the other side, not shown, but they're flat brass buttons. The trace at the far right is ground (goes to the metal ring in the mounting hole), trace at the far left goes to the harness connector, ground supplied by the door pins. The constant +12v connector has been cut off where it used to go to the bulb socket, it was all one piece.

The Toyota with the traces embedded in the plastic housing wasn't fun, I had to Dremel away the plastic to get spots that could be soldered to. I completely replaced the constant +12v pin for the harness connector with one I bent up from sheet copper and JB Welded in place, there was no way to keep the original after cutting out the center of the housing to add the aluminum plate.

Reversed polarity was the problem. I didn’t realize the leads on my meter were backwards. This is why I shouldn’t work on stuff late at nite. Now I’m going to take my dumb butt to bed. Thanks for the help though.

Ha! That sucks, but it's still better than never finding out what happened. :beer:

What’s all over those boards? That clear “potting” crap or flux?

Not coated with anything, at least not the ones I got.

Darn, I though you wanted help making them explode… that I can do… J)

That’s the way they came, so I don’t know.