[MrForbes]

Glad to help...and a bit concerned about our own robot, which uses the 36mm banebots gearbox/RS540 motor.

I could not see any way that the terminals could short out, so having shavings in there is a reasonable explanation.

The programmers finally got the 1726 bot going today, the arm now works as it should, driven by that little 540 motor in a 125:1 gearbox, with a pretty well balanced gas spring holding it up. Several students took turns driving/scoring rings, and the motor seemed to work fine, although it did emit a little bit of "warm winding" odor. Should be ok....but we're working on setting up a FP motor on a spare gearbox just in case!