I-177B Tube Tester Calibration

[drdave3]

I have been calibrating my I-177B. I got down to the mutual conductance test and encountered a problem.

I hooked one side from the AC source to pin 3 and the other to pin 8 on the test socket. I used the proper resistor, variac, and isolation transformer.

However, I got a very low reading on the GM test. It was nowhere near 2000 on the dial. I noticed on Bob Andersen's video that his came out just fine. I couldn't tell from his video how he had it wired, though.

What did I do wrong? I put the resistor in series on one side of the lead. Originally the meter went backward, as the instructions warned, but it never came up to where it needs to after I switched them. I can't see it being that far off. It is way off on all scales.

I am grateful for any help.