Chris G3VBL Pedder wrote:
For the last 37 years my Hallicrafter HT33A has been sitting on the floor
in the garage with an 8295A (Ceramic) fitted. I have a pair of 'new in the
box' PL172s one of whose boxes is still sealed. Packing date was 6/67 so
that's almost 50 years.
I suspect that the glass seals will have leaked but is there anyone with
experience of these tubes after such a long period of time. If I were to
construct a hi-pot device, what sort of values should I expect from a
'good' tube? Thanks.
There is a procedure to test tubes for gas intrusion, which I forget
other than it is done K to G with a completely cold cathode and about
300 Volts. google can be your friend
--
Ron KA4INM - Youvan's corollary:
Every action results in unwanted side effects.
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