One of the best experts on tube checkers today , especially on Hickok repair
and calibration , is Chris Haedt in Grand Blanc, MI.

He is currently doing some very scientific tests on the way Hickok testers
"run" the tube under test, and why certain testers do not seem to give
accurate readings on some specific types. This is the first time this kind
of research has ever been done to such an extent. Chris has published some
of his findings, I dont know where all are, but he could send or point you
to some of them I imagine.
If I were you, ask the cost for him to do your tester. He also has restored
testers for sale. It seems to me well worth it to have one of his full
restorations done. All my testers have been restored by Chris, and fully
calibrated, and it was well worth it.

I think Alan Douglas will back me up on Chris' abilities. He is doing some
groundbreaking work in this area.

reach him at:
remove NOSPAM to reply.

Mark Oppat
Antique Audio


"Henry Kolesnik" wrote in message
...
Hi

Both my Hickok Cardmatics, KS-15874-L2 have been mothballed for about 10
years and both exhibit the same symptoms as well as both Cal. Cells are
dead
(I've seen the reverse engineered schematic and wonder if anyone has had
success with repair or an external bypass.) I brought both up on a
Variac,
no smoke and both draw a little over a 1/2 amp. Cal. B+ indicates the
meters are OK . For example neither will test a known good 12AX7, the
meter
tries to go a little backward on Gm, and the 4 button lamp lights
indicating
a dual section tube. Does anything come to mind of where I should start
or
am I facing cleaning off the test bench and staring at hours of learning
the
circuits for basic troubleshooting each mechanical and electronic section?
I kind of feel that there's a common fault that someone with lots of
experience might point out.

tnx & 73
hank wd5jfr