I recently sold a demo man and the guy who purchased it reported that the magnet was no longer working yesterday. After running through some troubleshooting, the magnet once again works but the ball launch button no longer registers. I had him run through testing the button, then jumping at the switch, and finally jumping at the MPU board, J209-1 to J207-1, and still no activation in the switch matrix. Everything else in the row and column of that matrix tests fine. What am I missing here?

Yeah, I wrote this prematurely. Unfortunately I'm working a bit blind as he's new to pins. However, he's definitely getting his money's worth on pinball repair education right now. The cpu test was done wrong, so he got a new wire, connected the two pins at the CPU and it now registers in test mode. Had him jump the lines at the switch itself and it's not reading, so looks like a broken wire. Having him check continuity on both lines next and will post results from there.

Had him doing that temporarily until we locate the issue. He’s been awesome to deal with, though, as it’s hit or miss with first time pin buyers reacting to having to actually work on the machine from time to time.

So he just sent me a video where he was showing me that the right handle button was also not working. Sure enough, I can see in the background on the DMD he's in switch edge mode and the damn ball launch switch is closed. Looks like either the button is jammed, grounding, or just going bad, so had him unplug it and ball launch button works perfectly now. He'll be opening up the handle later, but glad we solved this mystery.

Thank you all for the advice and help!