Been working on my Slugfest getting it fixed up for the holiday season.
I've been spending time trying to get the ramp working right. Here is what is happening.

The opto stops registering. I have tried all of the following:
Replaced the Opto board
Replaced both the transmitter and receiver optos
Added lockwashers to the opto screws to stop them from coming loose and causing the optos to shift.
Resoldered and tightened the wires on the connectors and motor.

In all cases the ramp works fine for a few games, maybe a dozen innings, then the ramp optos stop registering. After I do another of the above the same pattern, ramp works then stops.

Only two things left I guess, Replace the connectors with new .156 headers and the MPU. Did I mention this is a repaired MPU that had some battery damage at one time. I would like to avoid the expanse of an MPU, what other ideas do you have?

Thanks in advance, Big Al from Chicago.

Solved the problem with the ramp. The switch row connector on the MPU was damaged. I replaced with a KK style but now a new problem.
Row 3 is out. My right bleacher and dispenser prize optos are showing in and out in switch edge test. The other analog switches on the row are out too. The work occasionally but go dead after a few minutes. Thinking a mechanical problem with he wire after replacing the connector but I've double and triple checked as well as tested with an ohm meter.

I pulled everything apart and ohmed out the White Orange cable and cannot find a hardware problem. Any other tips?

https://photos.google.com/share/AF1QipOIIJomtLDfaNMDYlcAR3YDFWEFwJlLkrpUrU5d8C3j3PBx1X4cfJayMi5jZluOjA?key=azJ5YUtxRFRQWlJWVFgxYmJlNlNwMEJCdHNEUUN3

Still have the problem but I have it more defined.
I tore apart all the game wiring harnesses looking for a short.
I pulled all the game interconnects apart to narrow the problem down to a specific section of the cable
I made a test wire for that row that came off the board that i could clip directly to a switch

In all cases the same symptom,
When the game is initially booted the switches work properly for about 5 minutes then they fail.
I put all the wiring and the game back together as professionally as I know how. The problem is the same. Row 3 fails after about 5 minutes.
I did not want to replace the MPU, I'm on record as being against throwing boards at problems. But I have been all over the wiring and am confident it's not with that.
The MPU I am using had been repaired at one time. It looks good now but there is enough doubt I will try a new one.
Fortunate that we are in a time where brand new boards can be had. I ordered one from Ks that I need to switch the chips over to. It should be here today so I'll update in a couple days with the result.

There is a Slugfest group? I will look for it. Thanks.

Just a follow up. The replacement MPU fixed the row problem. If I had to make a guess it was a bad filter cap on the row input.
The ramp is running properly as are the remaining switches on row 3.

One last thing. The optos appear in test as normally closed switches. It is a red herring to trouble shoot optos showing up as closed in switch edge test.