I bought a well-used TIC ring from another ham. It had been up at least
a decade and had several problems. During the course of rebuilding it I
learned a few things about how they work and what can go wrong.
My TIC ring was very rusted. It had the wear you describe on the small
rollers. It also had a bent shaft on the output of the motor, which has
the small gear. In the course of repairing the unit, I think I came up
with a hypothesis on how the shaft got bent.
With a lot of patient and careful work I was actually able to straighten
the shaft by bending it back into true. I would not recommend this, but
it was necessary because a replacement motor was not available from TIC.
Next I reassembled the ring in my basement. I found that because of wear
on the small rollers, the rotating part was making contact with the
fixed supports. You could see wear on the fixed supports. I was able to
obtain replacement small rollers from TIC, so I replaced them all. This
restored clearance between the rotating part and the supports.
Finally, I found that even with the spring loaded roller properly
adjusted, due to wear on the large lateral rollers and the outside of
the ring, there was excess play/clearance between the small drive gear
and the ring. The lateral rollers were clearly worn down in the area of
contact with the ring. I think that wear on the lateral rollers and the
outside of the ring increased the clearance beyond spec. The cure for
this was to elongate the mounting hole on one of the lateral rollers so
it could be mounted closer to the center, thereby taking up the
increased clearance due to rust & wear.
I hypothesize that the increased clearance allowed the ring to slip as
you describe. I also suspect that when this happened, the small gear got
'out of sync' with the large gear, resulting in contact between the high
points of both, which jammed the rotor and caused the shaft to bend.
Bottom line: I would strongly advise fixing the clearance problem before
using it further, as you may suffer a bent shaft, which will be a bad
thing, as the motors are not currently available (unless its a newer
version than mine).
Tony, K1KP
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