I may try prying them open as well so as to be a bit more careful about how I'm cleaning things in there.
Thanks,
Barry - N4BUQ
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----- Original Message -----
From: "Richard Knoppow" <dickburk@...>
To: [email protected]
Sent: Friday, April 10, 2020 1:45:25 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 334A Balance Pots
?? 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.
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
--
Richard Knoppow
dickburk@...
WB6KBL
