[TenTec] PTO?

W9SN nw9g@netusa1.net
Tue, 26 May 1998 23:03:28 -0500


rohre wrote:
> 
> John,
> I think the grease performance might be influenced by such factors as ambient
> humidity, temperature, dust in the shack, as well as age and use.
> 
> What happens in the grease failures, is that the grease dries out.  That is,
> the volatile solvent like components evaporate, and the remainder becomes the
> gunk that traps any dirt or dust and that leads to the symptoms well known to
> the Ten Tec PTO long time users.
> 
> Certainly heat drives off the lighter compounds, but very dry shack conditions
> might contribute as well.  I notice you are from FL, where the humidity might
> be higher than other areas, lessening evaporation of volatile solvents.  But,
> that might also depend on whether you keep your shack air conditioned at a
> very cool, and thus dry, temperature.
> 
> Perhaps, the grease that was used in your particular unit had a higher
> percentage of volatile components that liquify the material.  Thus, it has
> been slower to lose its new grease qualities.  Maybe the lack of use has
> caused a film of hardened material that kept the inner grease from evaporating
> the volatiles, yet it breaks free when you use it without symptoms of drying.
> 
> The choice of lubricants is a fascinating study.  I have worked with large,
> multitracked tape recorders for years, and the grease issue makes a big
> difference in the performance of older design recorders as to speed flutter.
> What you see in the PTO symptoms described by long time Ten Tec owners, is a
> very slow speed flutter effect caused by the hardened grease in the PTO drive.
> 
> On large recorders, we have had good luck on regreasing open ball bearing
> races with silicone ball bearing grease which is good for a wide latitude in
> temperature.  I wonder if any PTO rebuilders have tried to use such greases?
> 
> I gather the kits from Ten Tec have a non silicone grease, in that the
> greasing needs to be redone periodically.  The high temperature silicone
> greases last indefinitely, but of course might affect some materials like
> plastics.  Thus, I cannot say it would be better for this application.
> 
> Good continued luck with your PTO,
> Stuart K5KVH
> 
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-- 


I agree completely.  I'm not a grease engineer but I can say by looking
into many older ten tec rigs I can tell how much use they have seen.
It's like looking at the odometer.  Too bad you can't see this at the 
hamfest!!  The orginal pto were made primarily of brass.  This made the
them wear down quickly.  Looking at the grease, you can see the
discoloration from the brass particals mixed in.  The main brass race
will have a track wore around it where the ball bearings cut that
groove.
The newer pto kits now come with a steel race and will not wear as fast
and make particals that get mixed into the grease.  I have no comment
on the other factors like humidity since I know so little but my own
experience.  But after having 20 plus pto run through this shack I can
say I have looked at quite a few.  When ever I pick up a rig at a fest
that has a pto, I just call ten tec and order that kit immediately.
All those rigs have got some age on them by now and usually need it
done.
I've seen alot of guys sell those rigs thinking there was a major 
problem when all they needed was a pto rebuild.  Good luck all....
and keep ten tec'n.....

                      ------------------------------------------
                                Steve Narducci                 
                        Amateur Radio Station -  W9SN
                          All Ten Tec Equiptment         
                          Toys for "Real" CW Men     
                      ------------------------------------------

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