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SMPS Controller shotguns relay across the pcb with magic smoke
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Porenbeton:
Just thought I'd share this somewhat funny failure on the pcb i am currently repairing from the control board of my dishwasher.
You see that tiny hole in the side of this IC?



Yeah not much to look at, something just shorted out internally, now the high voltage DC side is shorted to the 12V DC output side.
Fortunately a fuse blew, so nothing much besides this controller is toast.
However i wouldnt have even seen this hole if not for the (though only superficial) devestation it did to the pcb.
First I though that a trace vaporized from some really high overcurrent, but it looked too directional.
Only with a magnifier could I see that it actually came from the IC.



Look how much magic smoke dispursed on this board from this tiny hole. There was a transformer in the way that i removed, it shot right past it,
but didnt actually even taint it.
The funniest thing is, the distance it impacted with the relay was about 50mm, the dispersion diameter however on it was only like 4mm.



That magic smoke puffed out of this hole hellish fast, wouldnt be surprised if it went supersonic for a split second even haha.
TerraHertz:
Wow. A magic smoke laser.

Shorting HV to LV side that time may not have been a disaster, but in other systems using that part, maybe it could be.
station240:
Ah it's one of those controller+mosfet in a DIP 87 package, with the missing pin.
The blow hole is between the Source and Drain pins of the mosfet, so the mosfet itself blew up.

I'd imagine the smoke was quite high pressure by the time the epoxy was finally breached.
tom66:
A great deal of these appliances use non-isolated converters because there is no user access to any exposed metal parts, connections, etc.  This is fine until the controller IC shorts I suppose.  If there is a transformer no harm can be done to the LV side.
 
I would expect a lot of components on that board to have been damaged by having the 12V bus momentarily jump towards 300V+.
amyk:
Those ICs are used because they're cheap, and are rather sensitive to input power surges.
I suspect that's what caused yours (and countless others) to blow up.
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