Hello, I'm looking for some guidance. The left target bank on Pinball Pool is controlled by a light driver on the DB, (Q17 I think), which drives a under playfield transistor. Both Ace from Ni-Wumpf and I have tested the light driver as good on a relatively new Ni-Wumpf DB. I got 2 different under playfield transistors from Cheesebay and neither worked, so I order a few equivalents from Mouser thinking the eBay ones were bad, but still no left targets reset. These all diode test as about 600 on one leg and no short. The game works perfectly otherwise. I did a continuity test on the purple wire that goes from the under playfield transistor to the driver board and it tests OK. I have A Ni-Wumpf MPU as well as new connectors and a new MPU to DB connector. What am I missing?

Thanks

Those are all good questions.

Did you try and manually reset the bank? If so, does it feel like a clean movement or possibly binding?

The coils are new because for some reason they melted a bit internally recently. Related? Maybe. Yes they move freely.

Did you work on the pin for something else and then this issue started?

This has happened before to the under playfield transistor. I replaced it and it was fine.

Yes, I lost a couple digits on a display, ordered a used one from ebay, installed it and several things stopped working. I sent the MPU, CPU, and the ebay display to Ace at Ni-Wumpf. He tested all three and said the display and DB were fine but the CPU Had a blown chip, I forget which. Got them back installed and everything is fine except the left targets don't reset.

I believe there is a mod I need to do once I get it working, that involves putting a diode in the chain which Gottlieb did later, but I don't think that is what is causing it not to work. It may be the reason I've had several problems though.

You can be sure I visited there first.