In article ,
wrote:
Assuming that the trim servo in question is not part of an installed
autopilot with pitch/trim authority, it is probably a PET-1 servo
(Piper Electric Trim).

You are correct, it is the PET-1.



Have you verified that the clutch is slipping, as opposed to the cable
slipping on the capstan? Both are typical problems.

I have not. It is possible that the cable is slipping on the capstan.
Right now, the airplane is in the hangar of an on-field maintenance shop
because I'm having an avionics guy look at my strobe noise problem. I
thought it would be a good opportunity to have the local A&P address the
trim problem, which he's willing to do, but he has no experience with
this type of problem. The mechanic has located a source for the service
manual for the PET-1. I just hope that if he gets it, he will be able
to diagnose and repair appropriately.



JKG