393 Motor self-stall, huge load

So upon testing my robot a couple days ago, one of our motors somehow suddenly self-stalled itself and thusly stalled the other motor (in the drive train).

Upon removal and inspection of the first motor, manually turning the motor was very difficult; not enough resistance to cause me to break the motor/gears, but there was definately something stopping the motor from turning. Removal of the internal gears and powering the motor via the 9-volt still causes the motor to self-stall.

Inspection of the actual motor (without removal from the casing) reveals no sign of electrical shorts between the red and block wires. Turning the actual motor has a considerably larger force than a normal motor. Has anyone else had this problem, and if so, what was the cause?

the brushes in the physical motor is damaged
its pretty much irreparable :frowning:
we have like 6 of these in the back storage room :frowning:

Our motors were not running well also. I went to my local auto parts store and bought a can of electrical parts cleaner and got 60W shock oil from a hobby store. I cleaned our the motors with the parts cleaner and drained it then lubed it with the shock oil. It may not help you now, but it should make your motors last longer and run smoother if you do some maitenance on them.

The thing is, a few weeks before this, this motor was given a good lube to its gears. It hasn’t been used heavily until the past couple days; would the lube have caused the issue with the brushes?

how much did you use? You only want to use enough to keep the gears wet, not have them soaked.

I didn’t actually apply the lube, but by no means was it drowning. The gears were greasy when I was inspecting the motors, but there was no dripping from the gears or anything of the sort.

Hey I have some electrical cleaner if you want to use it.