[Collins] Collins 32v3

[Dr. Gerald N. Johnson]

On Sun, 2007-03-18 at 10:34 -0500, zilassoc at sbcglobal.net wrote:
> Bill,
> 
> This is possibly one of the most difficult pieces of Collins gear to restore 
> and work on!
> 
> It weighs 110 pounds and is not easily manageable on a workbench.
> 
> It is loaded with those old mica postage stamp capacitors that have lived 
> their useful life by now.

Some of those flat molded capacitors are actually oiled paper the
forerunners of the infamous black beauties. Micas can go bad too, just
they aren't so guaranteed to do so as the oiled kraft paper capacitors.
> 
> These caps are in 'almost' inaccessible places under the bandswitch or 
> hidden inside coil covers.
> 
> The Erie ceramic trimmers are a high failure rate item and a nightmare to 
> rebuild or find replacements.

Those are getting to be a real pain in S-line too, though the ones in
the 32V are probably even larger. Maybe a small chunk of printed circuit
board with a more modern trimmer can be made to work, but the relatively
large RF voltages (and hence tuned circuit currents) in the tube
transmitter may mean the tiny modern ceramic trimmers will never be a
satisfactory replacement unless they can be paralleled with a fixed
dipped silver mica to divert most of the RF current away from the
trimmer. But that requires a different fixed capacitor for each
application that has to be determined some way, that would be easy if
the original trimmer worked... But if the original trimmer worked it
probably doesn't need to be replaced.
> 
> The B+ wiring was done with some kind of wire that disintegrates totally 
> with time and shorts the B+ to chassis.

Varnished cotton probably. If it hasn't fallen off, perhaps some motor
winding varnish applied to the cable harness would hold the insulation
for a while longer.
> 
> Did I mention that it weighs 110 pounds?

may it needs to be mounted in a frame with pivots on the ends like some
builders of scale steam locomotives do for their building process. I saw
one recently with a couple posts with pivots, that used a car jack for
raising and lowering each end.
> 
> Anyway enough of the negative stuff. When you get it working, it punches out 
> one heck of a strong good sounding AM signal. I used mine all the time of 
> the CCA 10 AM net several years ago when the band was open.
> 
> Good Luck
> 
> Vy 73
> 
> Pete Zilliox
> 
> K5PZ/6
> 
> ----- Original Message ----- 
> From: "Bill Campbell" <wd4hen at bellsouth.net>
> To: <collins at mailman.qth.net>
> Sent: Saturday, March 17, 2007 9:36 PM
> Subject: [Collins] Collins 32v3
> 
> 
> Hello All,
> 
> I have complete 32v3 that i would like to get working.  I know next to 
> nothing about it's history.  The fellow I got it from thought it was a 
> receiver hi hi.  He did say it had been sitting in a barn for years.  This I 
> believe since it was filled with acorns when I pulled it out of the cabinet. 
> The cabinet is in rough condition but I can refinish it with little (a 
> lot!!) work.  The front cleaned up very nicely and I got the trash from 
> inside.  Here is my problem, my technical skills are not where near 
> sophisticated enough to restore this unit to working condition.  So I am 
> looking for someone within driving distance with the knowledge and 
> sophistication to do the job right.  This unit is way too nice to be parted 
> out or junked.  If you know someone or you would be willing to work with me 
> on the restoration I would like to hear from you. All ideas and/or 
> suggestions will be greatly appreciated.
> 
> Bill - WD4HEN
> Florence, Alabama
> 256-760-4253
> 
Another serious point of failure can be the transformers. It would be
good to dry them gently before applying full line voltage. One way would
be to short the secondaries, and then apply a low voltage to the
primaries to get rated current through the windings to warm them up and
dry them out without applying enough voltage to breakdown through the
damp insulation. It certainly would not hurt then to remove the covers
from the transformers when possible and to brush on some more
transformer or motor varnish to the exposed windings while they were
warm, hoping it would soak in and hold moisture out and get into places
where the insulation had crumbled. It would be optimum to remove the
transformers, and have them vacuum impregnated in a motor shop, but the
damage to the wire leads taking them out probably is more than the value
of the impregnation.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer