I have offered to take a look at my friend’s amp after they accidentally wired it up backwards. Expecting to find some physical damage or any number of damaged components, I opened it up (after checking all the fuses with a multimeter). Nothing visible at all, so I hooked it up to a bench supply. Protection light flashes, and then nothing. The voltage across what should be 13.8VDC had dropped to ~7VDC, but no smells, heat, noises…

It’s a 4*100WRMS (at 4 Ohm) amp that had no faults or funny business before very briefly being connected in reverse. I’m hoping an amp circuit guru will be able to see the likely components to check, as without a hint (visual or otherwise) I’d just be poking around in the dark.

Thanks for any tips in advance!

enter image description hereenter image description here