Accidentally applied 24v, instead of 12 and despite no magic blue smoke, it's dead now. The board's plus and ground are now shorted, when examined with multimeter. Visually, I don's see suspects.
Which component is, most likely, quit working, guys?
Well if you don't know what the IC is, there's no guaranteed way for you to purchase the appropriate replacement for it (unless you're willing to experiment a lot). You'd have to either ask the OEM for the circuit schematic (doubt they'd hand it over) or buy a new unit