FS: A-B pots; FFP: 515/515A manual

Brad Thompson


FREE FOR POSTAGE plus a cuppa coffee: one only 515/515A manual in good condition
(plastic spiral binder chipped, front cover missing small piece). There's no serial number
inscribed on the front page).

FOR SALE: I'm offering one batch of 32 pieces each of used/removed from equipment
Allen-Bradley type J potentiometers. These feature screwdriver-adjustment locking-shaft bushings and
are an unsorted mix of 10Kohm and 20 Kohm pots. They were used in rheostat mode
(soldered connections to wiper and one end). The original applications were unknown,
but were likely used as set points in fearsome analog kludge.

(Note: my long-gone RM515 used a 20K A-B pot as the -150V adjustment.)

For a detailed description and a source of NOS type J pots, go here:


I'm asking $13.50 for this assortment of 32 pots (with some mounting hardware),
which includes $8.45 for USPS Priority-mail shipment.

Questions welcomed, PayPal honored.

Thanks, and 73--

Brad  AA1IP


Q: how long are the pots' shafts?
A: they're designed for screwdriver adjustment and hence have stubby shafts unsuitable for attaching knobs.

Q: what's the resistance taper?
A: random samples appear to be linear versus rotation resistance-tapered.

Q: are these all tested?
A: sorry, no. There's a limit to my patience.

Q:  what's the power rating?
A:  they're spec'ed  for 2.25 watts. Ohm's Law applies to the entire resistive element.

Q: what's with the weird part numbers (e.g., CBZ xxxxx) stamped in some of the pots' cases?
A: it's a military specification.

Q: what's a kludge?
A: an inelegant solution using available parts and poorly-suited tools
     to expeditiously solve  a problem at hand. You'll know one when you see one.
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