Question on tube testing

vintage 5.0

vintage 5.0

vintage 5.0
I have a Sencore T162 tube tester. I received some Amprex 6DJ8 tubes older stock made in Holland. I tested them and they test good but on the grid leakage they are almost in the questionable area. It appears some of the testors including Sencore sometimes have too high of standard for grid leakage. I was curious if others have found this when testing tubes.
 
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On most 6DJ8, mine indicate no leaking.

Are your tester calibrated ? (Easy to do if you own (Have bought or build a calibration module as per the manual).

Sencore TC-162 calibration notes (When calibration module is installed on socket 1).

A (Pins elimination butons = All UP)

B. C. D. = (Butons)
Under = (Settings)

Leakage.
B. C. D.
1. D. 4.
Adjust R21 (Near the center of the board)
Needle Between Questionable and Bad.

Emission.
B. C. D.
1. D. 3.
Adjust R22 (Near the edge of the board)
Needle test 60
 
Last edited:
vintage 5.0 said:
I have a Sencore T162 tube tester. I received some Amprex 6DJ8 tubes older stock made in Holland. I tested them and they test good but on the grid leakage they are almost in the questionable area. It appears some of the testors including Sencore sometimes have too high of standard for grid leakage. I was curious if others have found this when testing tubes.
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I use a Heathkit TT-1A ( which is a great tester) and in the summer, the grid leakage test often shows a false positive reading. This is because they measure the leakage current across an 18 megohm resistor. I live on Long Island where it's humid in the summer and the moisture in the air causes a false reading by allowing a little conduction across the resistor. If I retest the same tubes in winter, no grid current. So, I disregard the test during the summer unless it shows up as a hard leak. It's a quirk of testing very high impedance devices.
 
Leakage calibration also affect emission calibration, so, you must adjust Leakage calibration before emission calibration adjustment.
 
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