Johnny Mnemonic Gearbox - Firebird Pinball

A Johnny Mnemonic machine we’d bought was having movement issues with the magnetic hand in the left rear of the playfield. It didn’t want to move left to right. The gearboxes were noisy, too.

Here’s how you clean the gearbox and solve the noise problems.

If you open the gearbox and it looks like this, the grease is old. You’re going to have to clean the whole thing and grease it up again.

We used Q-tips to get most of the gunk out.

There are two washers and a spacer bearing on the largest gear. Make sure to take them off and get them clean. The second washer is still on the spindle in the picture.

Don’t forget to get the grime out from between the teeth of the gears. We used a toothbrush to get in there.

When you get the mechanism back together, lube it up well. We used an automotive wheel bearing grease.

Get the whole thing back in the game, and yours should run as smoothly as ours now does. BONUS: Make sure the rubber spider coupling is there when you put the threaded rod back on the gearbox. (These couplings deteriorate and fall out.)

Here’s the problem with our left-to-right movement. The X-nut had been wearing unevenly as it traveled along the threaded rod, causing the hand to hang up.