I have had some luck by prying the covers off for cleaning and then crimping the tabs back. Can't be done where the pots are stacked. AB were the best of the bunch are a pain to clean. Ohmite sold these same pots under their own name. Same for fixed composition resistors, Ohmite and AB are actually all AB. Ohmite actually says this in some of its early advertising. I have no idea what the story behind this was.
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On 4/10/2020 11:30 AM, ebrucehunter via groups.io wrote:
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
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Richard Knoppow
dickburk@...
WB6KBL
