So the original opto PCBs were a bit hacked up and one array wasn't working. I ordered a new set from Gulf Pinball. I put the new PCBs in and one of the targets wouldn't work. I went through all manner of troubleshooting trying to figure out why. Everything seemed to check out otherwise. I finally took the target bank over to my friend @taylorva and we plugged it in his game. The bank was acting even flakier in his machine, sometimes none of the optos showing up in switch test. He replaced a few wires as we thought we had some that were partially broken. Still, no dice. We used an old digital camera to check the transmitters. They were nice and bright. We then took the PCBs out of the plastic bank and held them next to each other...BOOM, all targets register! Now, where does this leave us? A warped plastic target bank apparently. The top edge on mine was tilted down a bit. I guess this just happens over time for some reason. I don't know if the Gulf Pinball boards are more sensitive to alignment than the originals or the ones from Great Lakes. Maybe they are to help combat the bleed issues that some people had with the original boards. I don't know. Anyway, the goal now was to make the target bank assembly true again. In other words, the plastic sides that the PCBs mount into must be perfectly (mostly) parallel. I determined what the gap, between the top and the bottom, is supposed to be. I cut a piece of wood to slide between the two sides that would make them parallel again. Yes, my wood working is haphazard and quite ugly BUT it works. It's tucked away in the game and you'll never know it from the outside The pressure from the warped plastic does most of the work of holding the wood in place but I added some tape for good measure. I'm sure there are some other ways to achieve the same end result as well.