---Bally 6803 Control Board---
I am down to the final two playfield lamps (wired in parallel on the same circuit) that never light. I have tested the sockets, bulbs, wires, diodes, connectors, etc. without finding any problems. The bulbs are getting voltage, the board never closes the circuit to light it up.
The rectifier for this lamp (MCR106-1) drives two lamp circuits. These two bulbs are on the circuit that uses the "A" phase (J12-4 below). The bulb on the circuit that uses the "B" phase (J11-1) works as it should.
Does this mean my problem might be in one of my 6821 PIA chips? I am thinking about swapping them to see if a different light goes out. No risk in that, right? I don't have a known good 6821 PIA right now.