Help! Smoking relay...

[alfi27]

Hey guys,

After bracing myself for a long time, I finally took the plunge and wired up the relay PCB (this onehttps://www.tube-town.net/ttstore/Bausa ... :5910.html) in my heavily modified Jet City JCA20H, my first relay wiring experience ever. As you can see there are two relays, one is for a simple clean channel and the other is for a solo boost. It worked perfectly, the cleans sounded amazing and I was in heaven... for a little while. I decided to rewire the footswitch to make more sense with the order of the switches, and when I plugged the footswitch back in there was a bit of a spark and smoke. So I decided to unplug it and put it back in, and then it smoked like crazy... ONLY when the jack was inserted, mind. And there was also a very very small spark when I was pushing on the board, measuring the signal path of a wire.

I am 99% sure that the cause of this is a screw right underneath it, holding the main PCB in place and connected to the chassis/ground, so when plugging in the jack the board would be moving slightly and then shorting it out. But what I find really weird is, that even after I isolated the screw with a heat shrink cut open and some tape, it was still smoking. My theory for that is that the rectifier diodes (1N4007), which are the only components seemingly affected, were already shorted/blown and thus smoking because of that.

When I get home from work in a few hours I'll replace those rectifier diodes and try again, but even if it should work; do you think the rest of the board might have taken on some serious damage? This is an amp that I might consider selling, and I do have another one of those relay kits as a backup; but of course I need to identify the issue before eventually doing that. Also, if you have another theory than mine on what might have happened, please share! I'm a complete noob when it comes to relays and to be honest some areas of basic electricity, my experience doesn't go much further than doing preamp mods more or less exactly after a schematic...

Thanks!

[Stevem]

Sounds like what took place on you!

Whatever diodes you find shorted just clip them out on the top side of the board leaving the leads as long as you can and then tack solder on the new diodes, as this will save you from ripping the traces off of what is likely a cheaply made board.