If the A1 CPU board boots, I think I'd look for a bad bridge rectifier or cracks in the solder around the header pins on the A2 power supply as a possible source cause.

Steve
System 80, not just a job, it's an adventure

Cool, I like easy. The reset board isn't needed for home use. Be sure to unplug it at the reset board connector and not at TC1 on the CPU board if there are resistors installed there.

Steve
System 80, not just a job, it's an adventure

Have you tested the Q64 transistor with a meter and compare the readings to a known working transistor yet? Another way to test the transistor is to set the game into solenoid test 17 to see if the solenoid fires. If it doesn't, the transistor is likely bad. If it does fire, the cause could be a bad connection at the A1J4 to A3J1 interconnect.

Steve
System 80, not just a job, it's an adventure