I am bringing my IJ back to life after storage for ~10 years. I had acid damage on the CPU board and have just replaced with a new board. The game fires up and works "almost" perfectly. The mini-playfield goes through test and passes, but it kicks to the extreme right. I've manually tested it and it indicates it works (goes far right and thinks center is left). I can move it far left by repeatedly pushing the manual test to the left. Switches indicate they are reading. It just doesn't want to center.
I've taken the mini-playfield out, cleaned the optic board/sensors, but here's where I may have screwed up. While apart and having the do-dad arm (that goes between the optics to indicate right/left) off the shaft, I ran the test. When everything completed or stopped, the shaft on the motor did not stop with the flat side of the shaft pointing up. I (and please don't hate me) manually, with my hand, rotated the shaft to the correct orientation. I fear I have screwed something up but I would have thought there would be logic to figure out "center" when the do-dad was on and positioned between the optics.
Any and all suggestions are welcomed.