OK, so previously I tied the ignition pin to +12V directly to help me troubleshoot some alternator whine. It seemed to help. When I went to reproduce this experiment, I put the empeg back into the sled, touched the ignition terminal to +12V, it started to boot and then smoke came out of the right, back side. It also blew the +12V in-line fuse.

When I took it apart, I found that a via just below and to the right of the four pin power header was burnt out (some of the FR4 was charred!). There is a silver-looking, two terminal part (heatsinked power or'ing diode?) to its left. If it is a diode, it's toast because it measures as a short...

So any ideas? The schematics are not public domain even though this is an old product from a defunct company? Anyway, thanks in advance for any help you all are willing to offer!

Ryan