[NJARC] Repair Tip (Jack Benny and my Dad would be very proud)

[Harry Klancer]

John,

We *always* ignore you. ;-) Seriously though, you're
right. You can get it at music stores - that's where I
got it. Also, you used to be able to get powdered rosin
at sporting goods stores too. Haven't tried recently.

My homework assignment was a 1940 RCA console that either did
or did not oscillate, depending. The lesson I learned was
"bring your 'scope to the clinic". When I put it on the scope (at home),
the oscillator level was very low at the low end, and sometimes
just stopped, especially after it heated up. You could shock it
into oscillation, and then it petered out again. The problem
was the .0047 cap to the oscillator grid, I call it a "plain
brown wrapper" job, because that's what it looks like. And Marty,
you were right. It wasn't oscillating on the police and sw bands
either, because there was another of these beauties (a .0027) in
that circuit. Replaced them both, and doubled the oscillator
output level. BRING YOUR SCOPE!

Back to John. This set had a slipping hard rubber clutch on the
tuning shaft, and rosin works great on that too - even on
rubber that has hardened somewhat after 66 years.

                                Harry K





john ruccolo wrote:
> Visit our web site - See http://www.njarc.org
> _______________________________________________
> Folks,
> 
> Speaking of Saturday's clinic, I took home a "homework
> assignment" from the clinic, an early 50's RCA AM/FM
> set. Among the set's many problems was a slipping dial
> cord.
> 
> The dial cord was in good shape, and like most of us,
> I HATE restringing them. But it did slip badly. I
> thoroughly lubricated the tuning cap bearings with a
> "cocktail" of lithium grease and very light machine
> oil (LaBelle model train oil). That improved things
> considerably, but the cord still slipped.
> 
> I then took some violin bow rosin and scraped off the
> powder onto the loops of dial cord around the tuning
> knob shaft. I did this several times. Wow! What a
> difference! The set tunes perfectly now, and I avoided
> the nauseating task of trying to restring or
> tighten-up the cord.
> 
> My Dad was an avid amateur violinist, and gave me this
> rosin many years ago. I'm sure you can get it at any
> music shop.
> 
> Perhaps all of you knew about the violin rosin trick.
> If so, please ignore me! ;-)
> 
> Regards,
> 
> John
> 
> --- "VOURTSIS, PHIL, INFOT" <pv0301 at att.com> wrote:
> 
>> Visit our web site - See http://www.njarc.org
>> _______________________________________________