I'm working on a Theater that had a bunch of trunk/motor problems. What seems to have happened is the motor driver board had a leaky cap that caused the drive to fail and let the motor spin in one direction. That seemed to create knock on issues of breaking off the roll pin in the motor stop, ripping all the wiring up and stripping out the gear box. Unfortunately, with a brand new motor I'm still having problems. The motor will never fully set itself to the correct position even though all the optos are registering appropriately. In test it spins sluggishly and will never fully advance to the next position, instead coming to rest somewhere between 60 and 80% of the way between trunk faces. Anyone solved this? Everything I've read, probably half a dozen topics, seem to suggest this is a gearbox problem but I've got a brand new motor and gear box. Not sure what else it could be since it was doing the exact same thing with the old motor and gearbox.

Wednesday bump… still looking for some suggestions on this one.

Yeah, this is a pretty weird one. I’m going to look at it again today, maybe try swapping driver boards and see if whatver failure worked it’s way back there.

Oh my. I hope that's not the case but I'll do my best to test this when I get a chance. I've had no time to dig back into this project but my schedule will free up greatly in March so looking to get back at it then.

I was finally able to get back to this motor issue and I can now say that the above was the problem. To outline the troubleshooting process I went through...

The original motor/board combo was not turning at all. Ordered a new motor board, and since I could see some leakage from the cap I took the old board and repaired it. I then installed the new motor board and found the motor was working but not turning correctly... it would only advance about 3/4 of the way to the next position and stop. I made the decision to purchase a new motor assuming the existing motor had developed gear box issues prior to the the original motor driver failing. So after installing the new motor the problem was identical... would only turn about 3/4. So I put the original motor board that I repaired back in and the motor started spinning freely and working fine. Looks like the repro motor board I bought was the issue after all, and a faulty motor board can indeed present this symptom. Hopefully this helps anyone that encounters a similar problem in the future.