[R-390] Misbehaving Audio Pot

[Barry]

Yesterday, I opened that pot.  There wasn't a significant amount of carbon or other undesirables inside.  The track looked clean, etc.  I powered it up without the cover in place and when I rotated the wiper to the point where there's a gap between the ends of the track, the radio made the same sort of increase in gain (not surprising).

With nothing else I could see to do, I reattached the cover and the problem is completely gone.  I suspect the cover may have originally been attached with the stop rotated very slightly from when I replaced it and that might account for a different stopping point.  In any case, problem solved.

Thanks guys,
Barry - N4BUQ

> If my attempt to open and clean this one doesn't work, I'll probably get back
> with you.
> 
> Thanks!
> Barry - N4BUQ
> 
>> Barry,I have a new old stock 2.5K pot your welcome to have.  The shaft is 0.45
>> long from the c-ring stop just above the 3/ 8 diameter threaded shaft.Never
>> been used but well stored.Let me know .John N3JKE
>> 
>> Sent from AOL on Android
>> 
>>  On Wed, Sep 25, 2024 at 13:05, Roy Morgan<k1lky68 at gmail.com> wrote:   Get Caig
>>  FaderLube. Make tiny hole in the pot. Squirt and rotate control. If that does
>>  not work, find a different pot or take that one apart.
>> 
>> Is that pot linear or audio taper? Allen Bradley Type J pots cost over $50 each
>> new. (Do they still make them?) One of those will last the rest of your life.
>> Roy Morgan
>> K1LKY Western Mass
>> K1LKY68 at gmail.com
>> 
>>> On Sep 25, 2024, at 11:10 AM, Barry Scott <72volkswagon at gmail.com> wrote:
>>> 
>>> 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
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