There was smoke..but R4 and R7 look fine. I can unsolder and check them if needed. I'm assuming that a good Q1 is not shorted drain to source...I'm finding it a little interesting that this circuit is so simple I could just replace everything that's not a resistor...but what fun is that?
The R4 and R7 won't smoke even if an output transistor shorts, but they will get hot to the touch if it does.
When testing the transistors, connect the red DVM lead to the upper lead on the schematic; that is,
the lead closer to the positive power supply. Replacing the matched pair of input transistors is not cheap.
Was there something that happened that caused the problem?
If it survived a shake table, that channel should be good to go.
Check all the parts on the bad board, there aren't many.
Look for resistors of the wrong value, or shorted fets.
Rayma: did you see my post #7 above? is the Q1 in question fine? from gate to either S or D is open....
fresh ones in the pack read 5.66M from G-S or G-D. Should I unsolder the output MOSFETs and test those?
I'll try that in the morning....
The input wires aren't reversed.....I redid both channel's input wires today.....the other channel still works fine....shorting plug in the morning...The other channel didn't smoke for months while the amp was driving the sub/shaker table from the good channel...nothing was connected to it.