[TenTec] Century 21 audio hum

Paul Christensen w9ac at arrl.net
Tue May 30 19:39:37 EDT 2017


I'm a firm believer in synthetic grease - but the right synthetic grease.
Look for Mobil 1 and Valvoline Synpower products.  It's a light, almost
fluffy grease with texture much like spackling compound.  Unlike
petroleum-based axle grease, it doesn't age.  

I first used Tri-Flow grease on a Drake 1A tuning mechanism and the result
was an absolute disaster.  It was so bad, I thought the gear reduction
tuning mechanism was destroyed.  This was not a fault of the Tri-Flow;
rather, it was my failure to understand how pressure and Teflon (PTFE) work
together.  Tri-Flow is a PTFE-based synthetic grease.  The moral of that
story is never, ever use a Teflon-based grease on high pressure points.  It
may seem trivial, but large pressures are present in some dial reduction
mechanisms. Teflon grease breaks down under high pressure and causes gear
seizure.

After a complete disassembly and cleaning of the 1A's tuning mechanism, I
then used SynPower grease.  The difference is incredible.  The 1A now has a
velvet feel that hasn't changed in several years.  This is not to say that
Tri-Flow won't work on the Ten Tec PTO.  Obviously, it does as there have
been many happy users.  I can say that the success is due to the synthetic
nature of Tri-Flow and that the PTO also has no high pressure points.   But,
unless you have a specific need for Tri-Flow (e.g., as a water sealant), I
recommend using the Mobil 1 and Valvoline SynPower products in these
applications.    

Paul, W9AC

-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Greg S via
TenTec
Sent: Tuesday, May 30, 2017 6:27 PM
To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Cc: Greg S <oldlongbeard at yahoo.com>
Subject: Re: [TenTec] Century 21 audio hum

I have used Sil-Glyde grease with great success. I can vouch for the fact
that parts are not normally needed. But you will spend some time cleaning
that old, dried farm implement lubricant they used ;-) Greg, KC8HXO
--------------------------------------------
On Tue, 5/30/17, Howie WA3MCK <wa3mck at gmail.com> wrote:

 Subject: Re: [TenTec] Century 21 audio hum
 To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>, "Josh Gibbs"
<Gibbsjj at gmail.com>
 Date: Tuesday, May 30, 2017, 6:15 PM
 
 Tri-Flow? What is that Josh?
 I'm familiar with the flush/clean procedure. I  have been told that 90W cup
grease or bicycle  chain lubricant is the way to  go.
 What say you?
 
 On Tuesday, May 30, 2017, Josh Gibbs <gibbsjj at gmail.com>
 wrote:
 
 > Sounds like its
 time for a PTO clean and re-lube! I've been reading  about  > that
procedure. Seems that  usually the PTO parts are fine and you just need  >
to clean out the old grease and get some  fresh grease in there. Some people
> seem  to recommend flushing out the old grease and then putting  some  >
Tri-Flow in there. Would certainly  be a lot less work!
 >
 > I hope Ten-Tec comes back to life and  starts selling parts again!
 >
 > Thanks for checking that hum for me. Mine  is definitely more than a
slight  >  hum!
 >
 > -Josh
 >
 > On Tue, May 30, 2017
 at 2:54 PM, Howie WA3MCK <wa3mck at gmail.com  > <javascript:;>> wrote:
 >
 > > Josh,
 > >
 > > Thank
 you
 > > for the info on the swamping
 resistor placement and installation.
 >
 >
 > > I have an analog C21. Bought
 it in the late 90's, had it on the air for a  > > few years, sold it to Joe
N2CX, he  had it for 15 or 20 years, and I  >  bought  > > it back s few
years ago.
 > >
 > > It's
 beat up cosmetically but works fine. Replaced the finals not  too  > long
> >  ago... and now the PTO is starting to go - mechanically that  is!
 > >
 > > Ok -
 just checked - yes, when I turn down the volume there is a  slight  > hum
> >  with my old 8 ohm mono headphones.
 >
 >
 > > I prefer to use the internal
 speaker which is fine for me and why I may  > > have not noticed the
low/level  hum.
 > >
 > > By
 the way, I emailed TenTec several months ago concerning  the  > >
availability of a PTO repair  kit for the C21 analog xcvr. I received an  >
> answer a few weeks ago stating that  they were in transition and to keep
>  an  > > eye on their website. Nothing  seen yet.
 > >
 >
 > Howie WA3MCK
 > >
 >
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 >
 TenTec at contesting.com
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 >
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