> I have some old headphones with a potentiometer volume
> control. Every time I
> adjust the volume, I get these loud pops and scratching
> noises. I assume
> this is due to bad wiper contact in the pot, probably due to dirt.

Three things:
1) Check that there is no DC component on the signal which you are sending
to the headphones.  If a blocking capacitor is dying, you might get DC, if
you get DC even a clean pot will sound like that.  It's quite common on old
audio equipment, but less likely if you have tried the headphones plugged
into several different sources.
2) I have had success in the past cleaning pots by carefully disassembling
them first then using a mild solvent to clean the track.  Sometimes it is
completely worn away, so that won't help
3) I've seen and replaced several pots where some form of 'cleaner' had
been squirted in, it's not usually a good idea unless you are prepared to
use gallons of the stuff (a little bit will often wash some abrasive muck
onto the pot track where it will appear to be fixed but do more damage
after a short time) and reapply any required lubricants afterwards to the
pot mechanism.

Nigel
--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk

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