dougrainer wrote:
This is a common problem. You have a BAD motor/trans assbly. By manually moving it you allow the armature windings to work. Doug
What ^^^DOUG^^^ said! Dead spot in the motor, and it's coming to rest right there. Just reading your OP, I'd've said that too. I don't work on a lot of RV's but many many motors, whether starters, pumps, windows, and so on.
Might just be a fouled spot on a commutator segment and I've cleaned lots of them up with good results. But reading through the load it bears, and Doug saying "common problem" I think it's possible that one portion of the armature winding, or its connection(s?) at the commutator segment(s?)
I have this "fix everything" mentality, and I'm trying to drive it at least into the background and do more "replace with new" projects. Especially when the system is critical or the labor to get into and back out of it is extensive.
Just thinking, is it possible those motors get damaged on the way OUT? We run it till the slide's fully extended but hold the switch a little longer? That would pass current through a stalled motor and surely heat it up even more than running it with slide in motion. My latest tinkering was a GM starter motor. I was amazed at how little run time it needed to get warm to the touch. And I was running it no load on a table top with a portable start pack. I'm sure your slide motor is a permanent magnet motor like this starter is. That means no windings in the motor housing, only the armature. So the armature's all that much hotter, to soak heat out through the magnets to the shell where I could feel it. Armature was probably too hot to hold.
