Once I went to a friend of mine and measured the potentiometer of the =
I-177 after fully disconnecting it from the circuit, and wrote down a =
table of ohms vs. degrees. I should have that table somewhere in the =
shack. That potentiometer, though wire wound, is highly non linear. I =
guess I would need the original spare part. I tried with a normal wire =
wound 3,000 ohm potentiometer but readings are obviously greatly offset. =
I also tried out to figure out a way of emulating the non linearity =
putting fixed resistors in parallel and in series, but unfortunately =
whatever one does the obtained non-linearity goes in the opposite =
direction w.r.t. it should be.

Do you have a 3,000 ohm non linear potentiometer to check?

Tony I0JX

"Scott Dorsey" ha scritto nel messaggio =
...
Antonio Vernucci wrote:
The I-177 tube tester has a very unusual non-linear wire-wound =3D
potentiometer.

Does anyone have an idea on whether any surplus store could have it =
on =3D
sale?
=20
How unusual is it? What taper is it?
--scott
--=20
"C'est un Nagra. C'est suisse, et tres, tres precis."