----- Original Message -----
From: "Rob Atkinson" <ranchorobbo@gmail.com>
To: <amps@contesting.com>
Sent: Wednesday, July 20, 2011 9:36 PM
Subject: Re: [Amps] Supply question
> Thanks for all the answers. Gettering an unknown condx tube at 1 KV
> sounds like a good idea--I had some idea of doing that but wasn't
> exactly sure what plate v. to use.
Anything around 1000V is fine as it wont sustain an arc. Apply enough
positive bias to get the Pd up to a nice dull orange for 10-15 minutes twice
a year for the spares or unused amp. Its a lot easier than trying to degas
3-5 or more years later and risk an unrecoverable tube. Long stored tubes
may require many hours and then retest with a hi pot. If it fails try again.
If it only shows a small leakage try in an amp or a test jig with higher
voltage capability with a big glitch resistor and HV fuse, a plasma arc may
be all thats needed to fully degass. My test jig can run up to 3500V, bias
is fully adjustable, lots of air and safety circuits.
>
> Whenever I run my 3-500zg they always wind up orange so I traded away
> my spares because I figured I probably would never need them.
Until it decides to let loose with a bang!
> Regarding gettering and filaments, the only thing I vaguely remember
> involving 3-500 filaments had to do with instructions to light them up
> when new for a few hours to get the thorium to change somehow--sorry
> for being so imprecise--this may be baloney but it must have had
> something to do with emission; not gettering. But with mine, I did
> not know anything about that and put them in, lit them up and started
> driving them and I have never known any difference. It very well may
> have been more 3-500 nonsense.
Since it is the same filament as the 3-400Z, 4-250A, 4-400A, PL-175 and any
number of clones the process is the same.
This is the best Ive read on the subject and altho the subject is antique
radio tubes the process doesnt change. Note the author is from Eimac.
http://www.antiquewireless.org/otb/rejuve.htm
My own experience has been mostly with amps in for service and in the
process I note the output is down a bit from new, say 10-20%. Rejeuveniting
has worked maybe 70% of the time; Ive no formal records on this but several
customers have reported years of full or near full output.
Carl
KM1H
>
> 73
>
> Rob
> K5UJ
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1390 / Virus Database: 1518/3777 - Release Date: 07/20/11
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|