My basement arcade has been a complete mess for the last four years.
Recently I figured out a way to somewhat break the literal logjam of games and I've managed to gain access to some games.
I'm slowly restarting games that have been sitting unused all these years.
I was going over Sea Island. Checking for sticking stepper units. Spinning by hand Control / Mixer and Magic Screen motors for unusual sounds and excessive drag from the clutch washers.
Spinning the fan blade of the Magic Screen motor armature. I heard some unusual clicking sounds from the gearbox. I Immediately suspected my old friend: the G-4114 intermediate gear. Maybe it had stripped as they commonly do.
I had a spare motor I had overhauled so I just swapped it in.
I was curious of the actual failure of the problematic gearbox so I opened it up:
I found some super dark almost solid grease. That's kinda usual for these old gearboxes. I inspected the gears and found they were all good. No broken teeth. But when I would spin the motor, It was skipping teeth... strange.
Looking more closely, I found the cause. The culprit was the shaft for the other intermediate gear. It's supposed to be pressed into the gearbox clam-shell housing on the armature side but somehow it became loose.
Causing over time for the shaft to wobble and wear out the locating hole on the output side of the housing. The locating hole became oval. The shaft no longer perfectly at a right angle. The gear wasn't meshing square with the adjacent gears.
The upside is that I now have a spare G-4114 gear. Th downside is that I'm down a Magic Screen motor, the gearbox being fatally ruined.
The rest of the game was OK-ish : I had to de-grease and re-lube the Magic Screen feature stepper unit, the Selection feature stepper unit and the Extra Ball stepper unit. I had to clean the payout unit discs and wipers. Clean the points on the Search Index relay switches.
I'm still play testing the game as I write this post.