I have a Gottlieb Monte Carlo with clean boards that boots and will play if I move the ball out of the trough outhole but there is a full row of switches that won’t register (strobe 6: #2 #4 #7 #9 drop targets, left return rollover, trough outhole) . In test mode with pinballs removed, all switches show open. Is this a board issue? (one of the Z chips) or should I be looking for something else like connector, wire continuity, under playfield wire, diode board etc? Thanks I’m not familiar with the 80B boards. I don’t have a scope. Is there a certain Z Chip associated with this switch matrix row that I can try to change? I don’t see any broken wires associated with any of these switches. Any help would be appreciated thanks.