Re: Tube condition

On Jul 21, 12:56 pm, zekfr...@xxxxxxxxxxxxxxxx (GregS) wrote:
I think I asked this question before, but never got any
good answers. I was checking a bunch of Telefunken 12AX7's.
I got different, mostly improved readings on the 539C tester by tapping
on the tubes. What do I believe ?

greg

Couple-or-more of questions:

a) are you using a socket-saver?
b) is the existing socket (or Socket Saver) nice and clean with the
individual pin sockets nice and tight?
c) have you let the tester warm up for at least 10 minutes?
d) and the tube for at least three?
e) and held the "test" button down for at least 30 second?

1. Dirty sockets and/or pins account for much. Don't attribute the
variation to tester faults until you are sure it is not a purely
mechanical issue.
2. Testers, even very good ones such as that C do not tell the entire
story.
3. Try tapping on the meter as well. Do you get the same changes? See
"purely mechanical" above.


Peter Wieck
Melrose Park, PA
.

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