BK Precision CRT tester (470)

[TinCanAlley]

Okay, I don't know if I'm having issues with this unit, or the socket is wrong.

I'm trying to test a monochrome CRT out of an IBM 5151 monitor from 1982. The tube number is quite long, but just using the first 5 from it I found a match in the testers list and it is the socket that fits. It is a 7 pin socket and the only one small enough and with the correct pins. I hooked it up, dialed in the heater voltage, meter showed 12V and the heater lit up. I then check for shorts, nothing. I then raised the G1 voltage to 50V and meter showed that voltage. I then tried setting the G2. This is where I have the problem. The manual says to turn the G2 until the needle raises ONE DIVISION. Now I am assuming that from 0 on the meter they mean until it move one marking. Only issue, the needle does not move. I know the monitor wants 270V on G2, so I'm assuming the tester should be providing around that. When I put the control to max, the needle hasn't moved, but when I press the emission button, it move to the GOOD range. If I hold it and reduce the control, the needle moves down.

Is there an issue with the unit or could the socket have a pin or two wrong? I know the heater pins are correct. If I were to probe the socket with a meter, which pin should I use as ground? I don't know if the heater ground is safe as I believe the heater and the other pins use different voltage types (DC and AC). So I want to measure pin 6 that is supposed to be G2 and I will use the red DMM lead. Where do I connect the black lead? Also, I don't plan on cranking up the G2 to blow my DMM, just enough to see if the knob causes an increase on the socket.

Thanks!