Martin:
If they are depleted from use then you don't need to any more of a test than
trying each one in with a good tube in a working fixture. If they light up
then keep them around.
As electricitym indicate in his reply post you should probably pair them up
with other used tubes. I usually replace them both at a time with two new
tubes in my double tube fixtures so I always end up with an odd amount of
good, used tubes that can be put into an easy access garage or shop two tube
fixture with just one bad tube.
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Best Regards,
Daniel Sofie
Electronics Supply & Repair
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"Martin McCormick" wrote in message
...
In article ,
Sam Goldwasser wrote:
First check for continuity of the filaments. Often, the open and that's
a simple test!

Yup. Open filaments are a show stopper all right.

These tubes all have good filaments but are old enough that
some, probably most of the cathodes, are depleted from use.
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Martin McCormick WB5AGZ Stillwater, OK
Information Technology Division Network Operations Group