potentiometer question...

[deadmeat13]

hi.
i posted this elsewhere on this site and no ones seen it or said anything so i'm reposting it. hope nobody minds.
I'm in the process of restoring a betalead (first time restoration) and the potentiometers with four pins are throwing me off. i've got the parts list it says 30K s Curve but I'm not turning up anything in a search. the four point pots are on the level, reverb, and master volume, although i'm not sure if they are the same ohms and whatnot. also, i believe all the others are 100k but the drive pots are 1 meg blue case and 1 meg metal case. can these be replaced with an Alpha Dual 1 ma pot?
thanks for your time, and sorry to be a newbie dummy,
mike

p.s.
also if you guys could point me to the best parts dealers that would also be helpful.
thanks!

[Enzo]

I saw it, wasn't sure what you were asking, and didn't have much to add.

Have you tried Deoxit in the old pots? Or are they broken?

The fourth leg is just a support, which keeps the pot in place while mounting the board to the panel. You can solder some extension wires to a regular pot and solder it in place. Once the nut is screwed down on the shaft it doesn;t matter.


What does the schematic identify them as? SOme pots must remain their proper value - as when used as feedback elements for an op amp - and others can be fudged - such as the common voltage divider "volume control."

[eikipi]

please

could you elaborate on what you mean by adding extension wires?

email earthismyashtray@aol.com maybe with said reply?

[defaced]

This maybe? http://www.alphapotentiometers.net/html/16mm_pot_8.html

[Enzo]

The parts I referred to are what we call Spider Pots. The four-legger you linked is a center tap.

Spider pots have long legs so they can reach down to the circuit board. Like this:

Peavey pot from AES.


The pot is like any other. The fourth leg is not connected electrically, it is just there for support. SO take a plain old pot of the right value and solder a couple inches of plain solid wire to each of the three legs. Now those pieces of wire can act as the long legs down to the board. Trim them to length later.