change of original components when restoring old radio or transceiver
sets is always an unpleasant. In the case of potentiometers
it is difficult to find double original potentiometers for RF/AF
or Mic/RF PWR.
you hear rustling in old potentiometers of your old transceivers
you need repair them with oil. My practice is to use syringe
with solid oil + spirit. Usually I use russian solid oil ÖÈÀÒÈÌ-203
(ÃÎÑÒ8773-73) . You can use SIMNIA
0, PETROLEUM JELLY S68OO,Mobiltemp SHC 100, AEROSHELL 15A or
good quality machine oil.
don`t must to open potentiometers, you must only press out some
oil with spirit into potentiometers. You must to turn the potentiometer
minimum 20 times from end to end. The solid oil hits to center
contact and will protect contact near axis.
This technique is very effective
and, usually, these potentiometers will still perfectly efficient.
But i know what in 5% of cases where the resistive surface has
been damaged and way with repair potentiometer by oil does`t
If you need new anti
log and log potentiometer- let see figure below and change your
old part to new 500k Ohm...1M Ohm potentiometer and adding resistor
Getting from : Electronic Instruments, MIT Radiation
Lab Series, Vol. 21