Quoted from Pookiegus:I have a sneaking suspicion the problem lies with the power supply rectifier board. It had been repaired with a quick hack - they cut some of the wires and soldered to other spots on the rectifier board!
How do I check that I have correct power at the rectifier?
The rectifier has test points just use a meter and see that the voltage is on them. They are all dc except for 1 that is Ac. The correct voltage for each is in the manual. If the rectifier has been hacked it’s probably because it had burnt pins on it and someone didn’t have the correct parts to fix it so the soldered the wires on to eliminate the connector. What I see more often than not but I have seen some crazy secondary power supply and other stuff to trying to get a stable power to sdb when all they really needed was to fix connectors.
First I would unplug J4 on lamp driver and MPU.
Once you get the right power on the rectifier I would then move to the solenoid driver board and make sure I have good power there. Especially on Tp2 Tp1 and TP3. Tp2 is the voltage going to the displays. Should be between 180 and 190v. Be careful this voltage is potentially lethal!! If this voltage is out the displays won’t work correctly or can be damaged.
Personally I almost always put a new rectifier in that era of game. The bridge rectifier on the factory one were barley big enough. I have had several games in to be shopped with old rectifier. By the time I change pins and try to mod it to make more reliable I could have put in a new one for less cost. I have had several go bad after a month or two of being back in service and then have to go replace. For 70 bucks you can get a new rectifier with new female connectors and pins. If your game has a old rectifier with burned pins and connectors start here.
This isn’t the issue with your game tho. As another pointed out the relay coil is 43v. It derives it’s power from the solenoid power on the rectifier. If the 43v dropped out the game would lock up. If there was no 43v game won’t boot. So your problem is more than likely limited to that solenoid driver board or the connector to it at J4 or J3 on the solenoid driver board