[Collins] 75S-3C PTO DIAL ALIGNMENT PROBLEM

[Jim Walker]

I need some help with a 75S-3C PTO mechanical alignment problem.  I
can't get the main tuning knob vernier control to properly engage the
dial assembly.  I cleaned a 75S-1 receiver this weekend and removed the
PTO and the PTO dial from the shaft with no problems.  When I was done
it all went back together with no problems.  I then did the same thing
with the 75S-3 and no matter what I do I am not able to get the vernier
to engage properly.  The dial slips when the main tuning knob is turned.

I have tried:  1. Sliding the PTO forwards and backwards in its mounting
and slightly moving it right or left to increase the tension on the
pinch roller.  2.  I made sure the large Bakelite piece on the front
panel had not moved which might have changed the alignment of the pinch
roller assembly.  3.  I took mineral spirits and cleaned the pinch
roller to make sure there was no grease in the assembly.  Too much
grease was the original problem where a previous owner had gotten
carried away and the grease had migrated into the dial.  4.  I tried
multiple times to engage the pinch roller and looked at the engagement
point through the viewing hole on the dial assembly.  I am at a loss at
what to do next.  I don't think anything is damaged.  What am I missing?
Is there a trick to tension the pinch roller on the inside of the dial
assembly?

 

Jim 

KZ5AW