Carl,
I have a Drake L4B that has been in the closet (sitting up as normal) for
over three years now and I just brought it out. I installed new 3-500z's in
about 1989-90 and am worried about the potential for problems. I also
replaced the diodes and filter capacitors about the same time as the tubes.
My plan was to bring up the HV supply slowly on a variac to "reform" the
capacitors and bring up the filaments to check the voltage on them. What
steps should I take to check for a gassy tube? Non-destructive steps :-)
If a tube is gassy, is there anything that can be done for them? ie:
re-evacuating?
Thanks,
Bill N4ALG
At 04:32 PM 2/24/97 EST, you wrote:
>
>
>Hello Robert and all.
>
>First of all the 3-500Z must be stored in a vertical position. Many
>friends have had the misfortune of buying a new set of spares only to
>find them shorted upon use many years later. All of them were stored on
>their sides. I'm not saying that it is a certantity, just that it does
>happen.
>
>The gas factor is one that I have been unable to pin down, possibly
>others might wish to comment. What I have seen, on occassion, is a
>customer bring in an SB220 or the like that has been idle for many years
>that has a gassy tube. As near as I can discover they were all Eimac
>tubes with 1985-90 era date codes. Those old 1970's era tubes seem to be
>bullet proof.
>
>Some of the early Chinese tubes had many problems which appear to be
>rectified.
>
>I hope this helps a bit.
>
>GL and 73 Carl KM1H
>--------- End forwarded message ----------
>
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>
>
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FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Sponsored by: Akorn Access, Inc. & N4VJ / K4AAA
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