[R-390] Misbehaving Audio Pot

[Barry Scott]

When I turn the LOCAL GAIN in my R-390/URR all the way CCW, something is
causing the audio to suddenly increase significantly.  It's just at the
very CCW position and I suspect dirt/trash/whatever is the cause and a good
cleaning would probably fix it.

Anyone opened one of these and successfully repaired it?  I've done that
for a lot of other pots very similar to this one and I think it's quite
doable but thought I'd ask here first.

If I can't fix it with a cleaning, then I think I could swap the internals
with another similar pot or maybe just swap the LINE GAIN pot with the
LOCAL GAIN pot as I really don't use the LINE AUDIO all that much (except
to watch the meter because that's kind of fun to do).  I'd just get another
pot but I'm not finding any just like it - at least not yet.

Thanks,
Barry - N4BUQ