I have been working on restoring a Bally Star Trek. I had it running for about 150 games and now my F4 fuse on the rectifier board assembly module blows immediately on power up. The issue first arose in the middle of a game with my nephew. I tried to reboot the game. The lights all come on, no displays and the game does not run the solenoid test fire or launch the rom.
At first I suspected that perhaps the fuse was just old so I replaced it and tried to boot the game and it gave the same symptoms-lights, no test fire, no displays. I then did a little research around the forum and saw that some F4 fuses would blow with a locked on solenoid. I checked all my connections, put a new fuse in and disconnected all the plugs from the Solenoid Driver board to see if the game would boot without controlling the solenoids to try to suss out if I had one locked on and I had the same no-boot immediate fuse blow.
I am attaching images of my boards. The MPU is brand new due to alkaline damage on the one that came with the machine. All the other boards are original. I noticed there is a little alkaline damage on the Lighting board that I need to clean off but I don't think that is my issue. have done the Vid Recommended Mods to the Solenoid Driver Board and replaced the caps. I have a little electronics experience but just need pushed in the right direction with how to solve this problem.