Quoted from djblouw:The lock relay is odd, because if I hold it closed with my fingers, and then release it will stay closed. Sometimes it will stay closed even when the game over relay is tripped (and everything else de-energizes).
Once the Lock Relay is energized at start up, it should remain energized until the machine is turned off.
If you jump the Lock Relay directly to the Yellow Common, does it stay locked on? If so, (and I would
guess that it will), then I'd do some jumping finding what section of the circuitry has the faulty connection(s),
maybe starting with the locking switches in the Lock Relay itself..