I'd considered doing that as well but I've read horror-stories where some "cleaners" have dissolved the carbon track rather unexpectedly.
Thanks,
Barry - N4BUQ
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----- Original Message -----
From: "ebrucehunter via groups.io" <Brucekareen@...>
To: [email protected]
Sent: Friday, April 10, 2020 1:30:10 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 334A Balance Pots
Barry,
I have one of these instruments, but it is too buried to easily allow
inspection to determine what type of pots were used.
If the values are above 1k, they are probably not wire-wound.? If they happen
to be Allen-Bradley (AB) pots, an age old remedy is to take a 1/16-inch
drill bit and drill a hole in the cover - in the outer crevice - at the
bottom of the pot away from the terminals.? The snout of a can of contact
cleaner can then be inserted in the drilled hole to blast the interior of
the pot.? This cleaning will typically last for two or three years and then
you might have to do it again.? The access hole remains available.? In
drilling the hole, metal chips seem to be pulled outward and are unlikely to
enter the pot.? But be careful so that when the drill bit breaks through,
that it does not enter and damage the pot.
Often these pots can be cleaned by pulling outward on the shaft -- it will
move about 1/16-inch -- while quickly turning the knob from end to end.
Bruce, KG6OJI
