"Ronald Walters" wrote in message om...
I have been using a MFJ-989C tuner for about (5) years without any problems.
Just recently I have noticed that on the higher band, 24 MHz that the SWR
occasionally would jump from an adjusted 1:1 SWR to infinity. A slight
adjustment of the roller inductance appeared to solve the problem although I
haven't ruled out a balum or antenna problem. I plan on investigating that
this weekend, however, before I open the cabinet and look for problems I
would ask the group for recommendations on cleaning the roller assembly and
inductor to ensure good conductivity after I am done.

I still have some old cleaning solutions from the old TV tuner days, some
electrical cleaner (Appears heavy duty stuff) but maybe there is some other
solutions someone might recommend.

Your thoughts and recommendations are appreciated

Ron - W4LDE

Theories on wiping, etc non withstanding, the usual cause of roller
problems on that tuner, " I have one" is due to gradual weakening of
the pressure of the roller on the coil due to the weak micky mouse
design of the coil. You can tighten it up by adjustng the little
things on the end, that are locked with a hex key. But be very careful
when you are doing this. It's easy to overtighten, and then it will
bind easier. A dirty coil could be the problem, but I bet it's that
coil starting to slightly loosen up from 5 years of turning back and
forth.
It then starts to "skip" at places, due to the lack of normal pressure
against the coil. I've had to adjust mine a couple of times. If you
coil feels overly easy to turn, compared to when new, that may well be
the problem. MK