wrote:

Thanks Ken......and you too, Charlie. It sounds like each of your
answers make a lot of sense.
The tube checker I have is a small compact model that does a large
variety of tube sizes....a Mercury, model 1101. I used to use a Hickock
(model 600?), but it quit working a number of years ago. I don't know
what went wrong with it, but it quit giving ANY reading for certain #s
of tubes, and I finally got frustrated enough to give up on it. I sure
wish I could find someone to troubleshoot it for me. The idea of trying
one tube in 2 or 3 different tube testers does sound like a great way
to go!

First thing to suspect in a tube tester is the (surprise!) tube sockets.
If they have been used a lot (and frankly, in most cases, most of us
would never know, since most of us buy our testers second- or
third-hand), it would be the first thing to check. The 9-pin and
octal sockets are used most, naturally, and are often just plain worn
out. Try tilting the tube to the side a bit and see if you get any
jump in the needle reading.

--Bob

================================================== =====================
Bob Ellingson
Halted Specialties Co., Inc. http://www.halted.com
3500 Ryder St. (408) 732-1573
Santa Clara, Calif. 95051 USA (408) 732-6428 (FAX)