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Jamie

wrote:

Hi all,
I'm repairing an old italian stereo amplifier and the volume dual
potentiometer is scratchy beyond any hope. I tried cleaning it and then
also dismantled it but the carbon part is too much ruined with several
pits. Also the two channels doesn't really track anymore, having large
differences in resistances in almost all positions.
The problem is that these potentiometers (47Kohm) have an extra fourth contact
which is at fixed position at 10K from one end. It's the first time I see
such a potentiometer with fixed divider. Does anyone know how to source
a suitable replacement?
Thanks in advance and best regards

Frank IZ8DWF

I ran into a problem like that once, only the one I had, the forth lug
was in the middle of the tap.

In any case, it's a custom pot and you most likely won't find one new
any where. On top of that, the pot is most likely a log type.

You can do as I did and it seem to work. Get the pots you need that
will fit, remove the tracks and drill a near by hole at the edge of the
track that fits the value you need. bring in a small wire to be inserted
into this hole. Use conductive cement, something like used in defroster
heater element repairs or circuit board repairs to bond and connect the
edge of the carbon track to this wire point.

When I did it, I used wire wrap conductor because it was small and
easy to work with.

Good luck.

Jamie