Have you rebuilt (disassemble, clean, and reassemble) the mixer unit on one of your games? If so, I hope you can give me some advice.
The background is that I have one game (Miami Beach) with a noisy mixer unit and another game (Key West) that has a mixer unit that is whisper quiet. The Miami Beach has an annoying metal on metal high pitched whine. I lubricated the motor’s gear case with 90W oil, filled the motor’s side oiler tubes with gun oil, hit all the clutches with neatsfoot oil, added a few drops of gun oil to the slot that runs along the mixer shaft. When that didn’t quiet the mixer unit, I swapped in a new motor that had bench tested as whisper quiet. No joy with that approach either, and the metallic whine is still there. It’s hard to isolate sounds along the mixer unit shaft because there are so many moving parts, but it sounds like the whine is pretty evenly distributed along the mixer shaft.
I’m wondering if disassembling the entire mixer unit, cleaning it, and reassembling it might make it quieter. If you’ve rebuilt your mixer unit, did it make it quieter? Is there anything else I might have missed?
EDIT: The game works perfectly in all respects, and I can easily rotate the mixer shaft by turning the fan blade. Everything works fine, it's just the noise that's the issue.