The random motor runs once the game starts until you shoot your first ball. It will also run when you have reset the timer by pressing the "C" button to start a search, and will stop when it finds a winner.

So depending on the behavior, that might be normal?

You say there are three random cams - there should only be one Random disc.

Hey, someone's got to do it!

Also, for some reason, even though Dixieland was mentioned, and I looked up the random motor's circuit on the schematic, I had earlier games stuck in my head. The earliest six cards in the 1970s had a single random unit. Now that BT has spelled the whole thing out for me, the lightbulb has gone off.

Thanks for setting the record straight baldtwit

The typical issue for this is that the timer unit is not stepping when the first ball is lifted, nor when any subsequent balls are lifted. This can be maddening as seemingly the rest of the game is functional, but you can play a neverending stream of balls.

In most cases, the issue is switch 2a on the ball lift motor cams. This little switch tends to get fouled easily. From the factory, there should be a shroud covering these lifter switches, but sometimes this is missing. It doesn't matter much as I've had to clean and adjust many with and without the shroud.

Regardless, this is always the first stop for me.

A second, but equally important stop, is cleaning the jones plugs. If those are fouled then there won't be enough current to step the timer even if everything else is working properly.