Help ID this pot

[fdesalvo]

Here’s a long shot, but have any of you seen a pot that looks like this? It’s in a dumble clone from an infamous and defunct builder of
yore. A customer sent me this pic and said he needs two of these in 250k. I’ve never seen such a small pot used in an amp before but obviously space was an issue. I’m waiting on some additional info and measurements, but a jog through google and mouser hasn’t yielded anything close.

Also, is there a way to donate to the forum aside from PayPal?

cheers

[Jon Snell]

Is it a pre set pot?
What are the dimensions?
Is it for biasing the output valves?
Make and model of amplifier may help and give us a clue.

I would check the part number in the service manual/parts list.

[loudthud]

I think what you are looking at is an old series of pots that were available in the 60's and 70's. They are 1/2 inch diameter and have a 1/8 inch shaft. See if you can find Honeywell 392JB, 392JA or RV6/392M series. Another possibility Bourns 3862 series. None of these are cheap. Check your local surplus store or online.

[Mick Bailey]

If the pots are noisy there may be enough gap to get some Deoxit in there between the wafer and metal shell. Otherwise, I'd be looking at uncrimping one and pulling it apart to investigate. The options for replacement are maybe to use a 9mm or 12mm panel mount rectangular pot.

[fdesalvo]

Thanks for the leads! These sit on a brown note dumble clone. The shaft is thin and about an 3/4” long. These are 250k used for fx send and return levels. The pot in question is broken. Shaft spins without coming to a stop. If not for this I’d attempt removing the wafer with the pot mounted, as the knob was epoxied on according to the owner. I bet he destroyed the pot trying to remove it. I’ll update with findings based upon your info and with specs after he measures.

[Mick Bailey]

Take a look at the Vishay PRV6 series - body is 1/2" diameter, available with solder lugs. Nearest value is 220k, but they're expensive.

[fdesalvo]

Excellent thank you all! I just took in the amp bad was able to remove the back enough to get some good cleaner in. Really appreciate the help.

[fdesalvo]

Wanted to close the loop. Found this little .51” diameter gem.$11-14. Thanks again for the great leads

[SoulFetish]

This type of potentiometer is a less common mil-spec pot which are called "RV6"

PEC Mil type RV6 Datasheet

I like using them as glorified trimmers, bias adjust pots, etc. They're great where you might need to make minor adjustments based on parts tolerances or tweaking something to "taste". They can usually be mounted close to the component because of their small size, and left alone once set.