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A little help with AU-717

PF Sound said:
It's starting to make sense. The problem isn't one side getting dragged down, it's that one side ISN'T getting attenuated when it should be. Per the schematic, leads 7/9 & 8/10 are essentially common on the volume pot, with leads 9/10 being attached to a 15k resistor when the "loudness" switch is off, & that resistor being bypassed when "loudness" is on. If lead 10, as in this case, is open then the signal isn't getting attenuated as it should be with the "loudness" button in the "off" position.

Unfortunately, this still means the pot needs repair.
Click to expand...
I do have stepped attenuator which would be almost complete 1 to 1 replacement. it is a very special pot. i have a thread about it
 
PF Sound said:
It's starting to make sense. The problem isn't one side getting dragged down, it's that one side ISN'T getting attenuated when it should be. Per the schematic, leads 7/9 & 8/10 are essentially common on the volume pot, with leads 9/10 being attached to a 15k resistor when the "loudness" switch is off, & that resistor being bypassed when "loudness" is on. If lead 10, as in this case, is open then the signal isn't getting attenuated as it should be with the "loudness" button in the "off" position.

Unfortunately, this still means the pot needs repair.
Click to expand...

Now you’re starting to think like a rocket surgeon.
 
TupolevFan said:
I do have stepped attenuator which would be almost complete 1 to 1 replacement. it is a very special pot. i have a thread about it
Click to expand...
Thanks for that.......I'll keep it in mind.
I took the back end cover off the pot & it looked pretty clean........very little grime came off when I cleaned the wiper. So I did the trick of spreading the sections slightly & getting some deox in there & worked it. Hard to know how a lead could go completely open on a unit that doesn't look abused.
At this point I gave the owner options. The pot wasn't causing any noise/static....just the problem of volume imbalance. I told him we could just disconnect the leads to the "loudness" switch & it will play. Or........I could take the pot apart & try to fix it, with the caveat that A) there's a chance I could fubar it, & B) what I find might not be repairable, at least by me, thus not worth risking "A". (being honest with him & myself).
He chose the former of the two..........just happy it works again. It's not how I like to leave something but I'm doing this job as a favor, & it would be no favor to get this far only to say sorry, I hosed it. We'll see how it goes. He knows where to find me if he's not happy with it.
 
That's a sensible way to deal with it - but from all I've seen @TupolevFan 's replacement pot is 'the business', really well done, it might even be considered an upgrade compared to the original. ;)
 
Hyperion said:
That's a sensible way to deal with it - but from all I've seen @TupolevFan 's replacement pot is 'the business', really well done, it might even be considered an upgrade compared to the original. ;)
Click to expand...
Couldn't find his thread on that after a quick search. I'd certainly be interested.....
 
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