I've repaired a few of these in the past, so this one was a pretty straight forward repair. With the top cover removed, I could see (1) PS FET had visible damage.
Because of the age of the amp, I opted to replace all PS FETS, gate resistors and drive BJTs. I removed all the parts and cleaned the PCB.
Next I removed and replaced the FETS on the MEHSA pads.
Finally, I soldered all the new parts into place, applied thermal paste, and mounted the board back into place.
Amp powered up and developed proper waveforms and created a proper output signal.