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

[Ian]

The "pinch roller" is adjusted by removing the main knob and loosening the
nut that holds the assembly through which the shaft rotates.  The assembly
is ECCENTRIC and you can rotate its position to tighten it on the plastic
that is part of the dial.  Cinch down the nut when the pressure is proper
between the pinch roller and the dial assembly.

Sometimes, even though it appears that the pinch roller part is engaged with
the plastic it isn't and I once had to try several times on getting one to
properly mate with the dial plastic and used a bright light to make sure
that it was mating.

Likely your main problem is the eccentric but do make sure that the parts
are mated completely and you are sure that it is gripping the plastic on
both sides and the alignment is correct.

I've sometimes moved the PTO a bit to make sure it aligns by moving the knob
with the screws holding the PTO loosened enough to let it be repositioned.

Ian, K6SDE


> >>-----Original Message-----
> >>From: collins-bounces at mailman.qth.net
[mailto:collins-bounces at mailman.qth.net] On
> >>Behalf Of Jim Walker
> >>Sent: Monday, February 26, 2007 5:46 AM
> >>To: collins at mailman.qth.net
> >>Subject: [Collins] 75S-3C PTO DIAL ALIGNMENT PROBLEM
> >>
> >>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
> >>
> >>
> >>
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