Hey everybody,
I'm a noob to pinball and electronic repair so here goes.

The game: Whirlwind, system 11b

So the original issue was that when certain coils would engage ("a" side of relay) the trough coil would engage, with or without a ball in the trough. Found my way to the relay test that shows the state of "c" side while switching back and forth between both sides. C side says that c-side is engaged. When it switches to a-side, it shows no information. The manual says it's supposed to say "err". Makes sense because it's displaying the state of the "c" side and if "a" is engaged "c" should show an error (because it's not engaged). That means there's some sort of crossover in the relay. (I'm talking like these are facts but please correct me if they are not). Let it rest for a little and came back to the relay test. Now when it would test the "c" side, the outhole kicker from the trough ("a" side) would engage. At some point the transistor for the outhole kicker from the trough shorted, I'm guessing from too much power going through it on the relay test as the test would hold the coil open for a period of time when it's supposed to be a quick pulse. So I replaced the shared transistor for the outhole kicker and (some c-side coil). Fire it up. They're not making the outhole kicker engage!! Woohoo! But.....nooowww there's a new problem. The 3-bank drop target coil makes the knocker knock Both are a-side of the relay. Cool test proves it's the 3-bank cool. Ok. Nutted up, replaced the relay with a spanking new one. Thinking it was crossing over there. Since the relay test isn't showing what the manual says, gotta be it right? No....no it wasn't. Like I said earlier, I'm a noob to electronics and pinball repair so I'm still learning the testing procedures and building my tool/tester selection. I haven't replaced the diode immediately after the relay or replaced the knocker diode (I replaced the outhole kicker diode earlier thinking it was that but it didn't change anything) the only thing that has really change the problem is changing a transistor. Anyone have any insight?

Hope I wasn't all over the place, lol. Any and all comments or criticism are welcomed.

Sincerely,
Some guy that has a problem with knockers

Also, I'm going to keep combing the forum and pinrepair

Oh, I also unplugged the pin connectors for the switch matrix and test each individually. They didn't trip any others. I'm going to do a little more testing on it though.

Cool, thanks for the material. Originally I had though a short between wires/connections but my problem is moving around. It used to be 7 out of 8 a-side relay coils would make the outhole kicker fire. Now it's down to the 3-bank drop target coil makes the knocker coil fire. Still on the a-side but different coils. I suppose it's not crazy to think the actions of unplugging and plugging in the board could change which ones are shorting. After my initial post I decided it's probably a good idea to keep a repair log, lol.

Oh and another thing I failed to mention.....which I think is important. The original problem was that the F2A fuse was blowing (short?). I'm not around the machine or schematics now but that fuse comes after the relay. It's supposed to be 2.5a but I put a 3a in. I know it's a no-no because things down the line could blow (I swear it wasn't my idea! it was the owners and I tried to say no). What other negative things can happen with a larger than required fuse?

I got it.....1/4" piece of solder laying on the backside of the CPU....right on the transistor pins. Here's to overthinking