Triplett 3444 testing of a 12AX7

[Aloha_Mark]

This is yielding a low reading of gm for the first triode section (P1) but a strong reading for the second section (P2). The 12AX7 tubes (both NOS and new) test fine with a TV-7U. Is this an inherent design problem with the 3444, or is there something wrong with the wiring or switches? Single triode tubes test fine with the 3444 in the P1 position. TYIA.

[Jazz P Bass]

Have you taken any voltage readings on the sockets.
Clean the switch?

[Aloha_Mark]

Will do as soon as I can find a 9-pin Pomona socket to do an in-circuit test. These sockets are rare. In the meantime, the backup tube tester is handling preamp tube testing.

[Jazz P Bass]

Don't know if you have this or not.
3444 Calibration procedure.
Link: Index of /pub/manuals/triplett/3444a/pages

[Aloha_Mark]

Thanks. I have added the calibration guide to my set of documentation. Time to change out the caps, check the resistors, and clean out all the switches.

[stokes]

My 3444 doesnt exhibit this problem,so I have to think its time to repair yours.These units are old,component values drift,caps fail etc.