I have a mystifying Switch problem on a Bally Playboy and I’m probably overlooking something simple.

Problem: Bottom pop, right outline, arrow rollover switches all work for a few seconds occasionally on startup, then die. These all share a common wire, brown/yellow, and pin.

Some tests and fixes I’ve tried:

Replaced MPU with Rottendog board

Confirmed continuity to each Switch from brown/yellow connector pin when plugged in.

Replaced all three Switch diodes.

Clipped off capacitors just to see if they were causing the issue.

Check to make sure no parts were touching these switches.

Some questions:

I don’t see another Switch with this wire but this diagram says “credit button” is on the same column. No idea what that is. There are no credit buttons on Ballys. This brn ylw wire doesn’t go to the coin door.

http://www.pinitech.com/switch_database.php?name=Bally_Playboy

Am I reading this wrong? I usually only tech later games with actual, documented Switch matrices with wire coloring info and such. This era of game doesn’t seem to have that...

Based on the manual I now think the credit button is the start button... did the diode on that for good measure. No fix.

I noticed that sometimes the rollover switch sticks closed, scoring infinitely, despite it clearly being open.

All great things to try. Thanks!

So this turned out to be the coin door credit button switch. I added insulating tape to a couple of surfaces in the switch stack and that solved the problems in the switch column around the playfield.