My intro post in the General area was getting too technical, so I'll start in here now.
Basically, I bought my first pinball machine and am beginning to work on it. The two major problems are Bonus lights 2-9 being out and a weak, unusable flipper on the lower left side.
Digging through the schematics, it's apparent that Switch Column 7 is not working since that controls bonus lights 2-9. I traced the wiring down from the Driver Board connector to the playfield light string and the continuity is good, so that rules out a harness problem and pretty much points the finger at the Driver Board. The column circuit is basically a couple transistors and IC14, so I'll probably start there. It could be the PIA but some research seems to make that unlikely since all other lamps work fine.
After some light cleaning, I could see that both lower flippers do, indeed, have the same coil. At first I thought they were different. I checked and cleaned the EOS switches but still no luck there. The flipper does not drag the playfield at all. The lower left flipper is still very anemic. I will be rebuilding them all anyway but I just have the nagging suspicion that something else is at play here. The fact that the wiring isn't quite the same on both flippers is making me antsy. I'm going to try Googling around for an under-playfield photo of the flippers so I can see if they are all like mine.
I also identified a couple other minor issues. When the ball gets launched, the horse gallop sound does not play. I think it's related to the switch under the ball while it sits in front of the shooter. That sound does play at other times, so the sound board is OK. Also, the TILT light doesn't work, although the functions do. I tested the slam tilt and the plumb bob. Both worked but never turned on the light even with a new bulb. I'll have to replace that socket next and see if that does it. The roller ball tilt is missing its ball, so I'll have to get one of those.
All the gameplay functions seem to work fine though, so that's a plus. Once the flipper is repaired it will be perfectly playable even with the lighting issues.
Any and all advice is always welcome...