Hi! Hoping to get some help figuring out an issue I'm experiencing with my Baby Pac-Man.
When I bought the game, it had some intermittent issues where occasionally, it wouldn't kick the ball out of the trough when you got to the pinball portion. At the time, I repinned some connectors, and got it back to working reliably for a month or two. Recently, however, there is no intermittent nature about it: The solenoids do not work at all. Putting the game into test mode, only the flippers will fire during the solenoid test. I repinned J6 on the driver board, and as far as I can tell, all the voltages coming through at the various test points on the driver board are what they should be, and the VCC pin from U4 has 5 volts...but the Q36 transistor and the solenoid 1A SB fuse below the playfield both get destroyed immediately, so clearly something is failing or shorted somewhere, but I'm not sure how to figure out what is going on.
I'm new to this stuff, and don't quite understand how to follow the schematics with confidence, but it looks like the Q36 transistor has to do with the drop target reset. I have also tried checking the coils and I think those are all reading as fine via DMM, the various resistors and diodes in the Q36 circuit seem fine on the board, I don't see any obvious shorts w/ wires hanging down anywhere or anything...I could definitely use some help in where and how to next look for a problem to narrow this down! I feel like it should be something obvious w/ the transistor getting killed and the fuse blowing, but as I said, I'm new, so
One thing I've wondered about, since the transistor seems to relate to the drop target reset, is maybe looking at the diode on the big coil next to the drop target bank, but it's facing the playfield so it isn't easily accessible w/o removing the coil, and I just haven't done that yet. Would that be anything that could cause this issue? Are there other things I can check under the PF while the game is in test mode maybe? I have also checked voltages at the fuse holder where the 1A SB gets popped, and I've got ~44V on the one side, and ~3V on the other (w/ no fuse in place), so I'm also a little surprised to see the fuse burst there unless maybe a coil is trying to fire during gameplay/during test mode and that firing causes a spike in the voltage? I’ve also confirmed there are no switches stuck closed.
Please help!