Got a DM on location with a weird cryo claw issue. About once every 10 times the claw is loaded, it never goes into the mode where the player controls it. The elevator rises, the claw picks it up, and... nothing. The claw will drop the ball, and it will eventually go into ball search. The game gets confused, and while it will repeatedly raise and lower the elevator, it doesn't seem to have any clue what's going on. This seems to happen more often when the game has been played a few times, but it's possible that's coincidence. I replaced the motor control assembly, but am still having the exact same issue. Because it's on location, it's difficult to test different options, and my boss just wants to leave the claw disabled. That's no fun for the players, though. Anyone know what causes it to kick into that mode?

Well, I found out what's causing it. Went back to the location today and played around with the DM after I fixed a few other things. Turns out, maybe one out of four times the motor drives the claw leftwards, it throws enough of a voltage spike that it's making the "claw left" opto activate. It only does it for a fraction of a second, but that's enough. So where do you put the diode in a case like this? I would imagine it's right before j1 pin 5 on the d.c. motor control board. Didn't really have the schematics on me enough to do it while I was there. Maybe next time.