I built a parallel LM4780 channel with some old parts I had lying around, including an old athlon cpu heatsink with the mounting bracket still attached. I also didn't isolate the chip from the heat sink, since I didn't have anything handy to do it with (this was a bad idea).
It was hooked up playing music on a test speaker when the mounting bracket (at V-) moved in a way I didn't realize it could, and reached under the board and hit the V+ rail. Sparks flew, I was right there, and I snatched the plug out of the wall in less than a second, before the slow blow fuse went. (I was using a 3.15 amp fuse, probably too much, huh?)
I hooked the amp up to a 12V AC power supply with good protection to see if it survived, the power supply wouldn't turn on ie. there's a short somewhere. My question: Where should I start checking for damage? Nothing is visually damaged except for the end of the bracket where it hit the V+.