If you haven't given up on this amp, check the 10 or so SMD transistors near the 494 for opens and shorts. Lift them to check for leakage if you don't find any defective ones in the other test.
Thanks again Perry. Checked all the transistors around the 494 chip. all checked good on both amps. No luck on these. You have to cut your loses at some point and move on. Leaving this final note in case someone else runs in to this problem. I wish them luck.
