Submitted by eeandersen t3_10pxwhy in DIY
Older Chamberlain 1245R. The drive sprocket recently failed (sheared/twisted off the shaft) which was replaced with a rebuild kit.
Now, on first start (no load, door not engaged), the motor stalled. A wrench on the sprocket "wiggled" it and the motor ran smoothly through 6 or 7 cycles but stalled again. The motor hums without motion.
So, what is most likely fault and is it repairable? It seems to me that the problem could be a dead spot on the commutator, a bad capacitor, a bound up gear???
Guygan t1_j6moexz wrote
Don't dig into repairing the motor. Just replace the whole thing. Far less trouble.