I had a relay magnetize that didn't fix itself with either a piece of tape or index card. I ended up degaussing the bracket using a soldering iron to remove the magnetism. Mine didn't start acting up until a few games were played. Powering it down and letting it sit for a bit fixed it short term. I don't know the game you are working on, but I don't think the magnetizing issue is real common in general.

Hate to ask, but what does the schematic show for those two relays (e.g. post the A/B circuit path so we can provide some valuable input).

The A/AR (man on 1st relay), B/BR (man on 2nd), and C/CR (man on 3rd) are interlock relays. All 3 (AR,BR,CR) are reset by the Hit Unit stepper's wiper disk.

pasted_image (resized).png

pasted_image (resized).png

A and AR are 2 separate coils on a single relay. There are several styles. Here's one example:

pasted_image (resized).png

Yep, just follow the AR and BR circuits... 95% likelihood it's a relay or score motor switch that is shared by both AR and BR circuits... schematic is your friend.

The AR and BR circuits are partially highlighted in my post above. The problem is likely in the Hit Unit stepper's wiper disk.

https://pinside.com/pinball/forum/topic/1971-gottlieb-playball-relays-a-and-b-not-working-correctly#post-6290961

Yup. Speaking from experience, my Play Ball had trouble correctly adding/removing runners from base. I messed around with the man-on-base relay switches, did more harm than good, undid that harm, then finally cleaned up the hit unit. That fixed everything.

My hit unit was occasionally sticking (missing steps), then jumping to skip over the missed steps. I partially disassembled it, sprayed alcohol to clean out all the old gunk. Lightly scotch-brite polished the rivets. Added a barely visible smear of PTFE (liquid teflon) Super Lube to the face of the wiper disk. Put a drop of lube in any joint that was metal-to-metal contact. New coil sleeve (NO lube). Works like a champ now.

Might not fix all your problems but definitely won't hurt.