Quoted from Mistermoberg:
Alright. So, I picked up a Bally Eight Ball a few weeks back. When I bought it, I was told the MPU was flaky (the board looks HIDEOUS) and that I had the option to buy the game with an Alltek. I declined to buy the Alltek. Three weeks later, game went crazy. Some light sockets refused to turn on, a little later, a chime coil stopped working. Did a power cycle - coils started locking on. Game stayed off, Alltek MPU ordered. Even if that's not the issue here - I should have an Ultimate MPU regardless.
Followed the install instructions exactly, checked for 5 on TP1, came in exactly at 5.25 - on the highest acceptable number, but in acceptable range.
Put in the Alltek, the game did indeed start up, but coils still acting odd, bulbs as well.
What's the next troubleshooting step here? Solenoid Driver? I really appreciate any help.
5.25, I assume volts DC? Measure the AC ripple there to check power supply caps. (This is not likely the cause of your problem, because usually a problem with the logic power will cause random or no boot up, and not cause the game to "go crazy")
Any signs of current or former corrosion around the battery area? This can spread like a disease when poor attempts have been made to clean.
Coils locking on random and other crazy usually points to logic problems, and if the boards have been worked on by someone inexperienced it would have to be gone through with a fine tooth comb. There could be wrong parts, solder shorts, trace damage - you name it. These games are also notorious for needing a LOT of repinning on the header pins and connectors. Go through the service docs for each board one at a time, performing any needed repairs and upgrades (there are a few for this series on each board), repin where necessary and then revisit the situation for advanced troubleshooting.