Hello, Tony

Sorry, I can't help you find that tube tester bias pot.

One thing, though:
I know the TV-7 manual gives voltmeter readings
versus bias pot settings, set up using a military DC voltmeter
of only 1K Ohm/volt sensitivity.
The available voltmeter ranges were 0 to 10V
and 0 to 50V, so the load across the bias pot
was either 10K or 50K depending on the voltage
to be measured during calibration of the bias pot.

I assume the I-177 was also intended to be calibrated
using a DC voltmeter of that sensitivity.

73,
Ed Knobloch


depending Antonio Vernucci wrote:
The I-177 tube tester has a very unusual non-linear wire-wound potentiometer.

Does anyone have an idea on whether any surplus store could have it on sale?

Thanks and 73

Tony, I0JX