[R-390] Squirrely PTO & SJC update

[Cecil Acuff]

My 2 cents worth is no!  I even cut the silica gel bags out of there because 
they couldn't have been contributing to reducing the moisture after all 
these years and I have read horror stories about them rupturing and 
spreading grit all over the inside of the PTO.  These radio's are not 
operated in the environment they saw during the wars....cold or hot. (wars 
that is)  Mine is in an air conditioned shop/shack and being in the south I 
heat it by vacuum tube when necessary...not unusual to be running the A/C in 
December....

Be careful not to spray cleaners or lubricants on the main coil form....bad 
things could happen.  I washed all my parts after removal and what cleaning 
I did with contact cleaner was done with Q-tips.  I did flow some over the 
lead screw while running the core in and out.

Just be careful...it wouldn't take much to reduce a perfectly good PTO to 
junk quickly!

Cecil.....
----- Original Message ----- 
From: "Tim Shoppa" <tshoppa at wmata.com>
To: <r-390 at mailman.qth.net>
Sent: Tuesday, February 21, 2006 12:23 PM
Subject: Re: [R-390] Squirrely PTO & SJC update


> Funny how some of us seem to experience the same type things at about the
> same time.....at times.  (confused yet?)
>
> I have been fighting with my Cosmos PTO for the last week of available
> evenings.  Same problems...got the jitters with reversing direction or 
> even
> when fine tuning at times. Tap on the PTO cover with a small screwdriver
> handle and the het tone would bounce all over the place. (most noticeable
> with the bfo on and using a heterodyne tone for discernment)

I've been doing most of my testing with a receiver on the bench in CW mode
to pick up the hetrodyne. It's a lot easier to hear the squirreliness than 
it is to
see it on a frequency counter.

That said, my squirrely PTO seems to have cured itself without me ever doing
any of the dissection that Roger or Cecil suggested. I did do a little 
cleaning on
the square rod that the spider arm rides on, and that may have been enough.
It had some visible deposits (maybe grease turned into shellac?) that might 
have
been hampering smooth action at some points on the dial.

Looking inside the PTO I see some greasy/shellacy gunk elsewhere but not
on the mechanics. After reading Cecil's success I am tempted to tear down 
and
scrub-bright and wash the whole innards.

Could the grease been intended to make the airtight/nitrogen-tight seal of 
the
cans against the O-rings?

Is there any purpose at all at this point to pump the PTO full of dry 
nitrogen again?

Tim.
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