Background information: owner tells me that a servicer came a week ago to solve a no-pumpout issue. She used the unit once after this, and described the sound it made as "like a toy with the batteries running out". I did not ask why she did not call the original servicer back...I would have.
No control panel lights, no response to keypad presses. I pulled the toe panel to verify power to the machine and see right off the bat that the hot and common wires are reversed in the junction box...so I already know something's fried. I know the keypad is FUBAR, no continuity between pins 6 and 10 (start function) during a key press. Both door switches and wiring show continuity through to the control board with the latch in the closed position. Beyond this point I don't know if it's worth continuing the diagnostics...no burns or other visual problems with the board, but am not sure how to test this without a working keypad.
Can anyone tell me how to test the board without a good keypad? Or is it more likely that multiple components have been damaged due to the reversed supply wiring?