Carl THANK YOU especially for that OTB Rejuvination article!!! I have never
seen that before and did not know of its existence--it is a major find!!
but also, excellent instructions on degassing! YOU DA MAN
73
rob
K5UJ
On Thu, Jul 21, 2011 at 10:10 AM, Carl <km1h@jeremy.mv.com> wrote:
>
> ----- 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<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<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
|