blue1004

I need your help.
My vintage proline transmitter, which has been gold stickered, is not working smoothly.
I found the potentiometer of the elevator is defective.
Is it fine to change the defective potentiometer with one of the potentiometers selling in the Radio Shack?
In this case which one is better, the linear potentiometer or the audio potentiometer?
The original potetiometer in the Proline transmitter is u-5K-Ohm Type J (AB 96829A).
Thanks.

Bob Laine

My Feedback: (91)

Send it to Tony Stillman, "Radio South". He's an expert on Pro Line radios for 30 or more years. Ad is in Model Avaition.

jlingrel

I agree, get Tony to change it, but just for information, the difference between a linear taper and audio taper is that the change in resistance is "linear" thru the range on a linear taper pot, where the audio taper has a greater change in resistance for degrees of movement at one end than at the other. If you put one in, you would have a really strange response on the control surface you installed it on. IE, greater movement on say down elevator and lesser on up.

John

fizzwater2

My Feedback: (61)

Like John says - you want the linear taper pot. The old prolines came with some really nice quality pots in them. Absolute best type would be what they consider a "hybrid" pot - it's actually wirewound with a conductive plastic layer on top that serves to smooth out the "bumps" as the wiper moves from one wire to the nest. Next best bet would be a conductive plastic, no wires. Next up - cermet or something similar, worst would probably be a straight wirewound with no smoothing layer, your controls would be jumpy.

Good luck, hope you find something suitable!

I remember brand names like spectol and bourns when I looked for pots several years ago.

NM2K

My Feedback: (14)

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Potentiometers made for occasional turning in electronics projects (Radio Shack) are not suitable for use in a radio control transmitter's stick assembly. They will wear out in no time at all.

Allen-Bradley used to manufacture the very special potentiometers used in upscale R/C transmitters. Finding some old stock would be the best thing. I do not know of a modern substitute that will provide the high quality that you need. Contacting Tony Stihlmann (sp?) at Radio South in the US is a good idea. He might be able to tell you of a good modern substitute potentiometer. Good luck.

injunnut1

The pot's face (and its wiper) likely just needs a good cleaning followed by a proper 'grease job'! This was common procedure with the old ACE red box transmitter stick kits back in the seventies. Also I have fixed many a 'jittery servo' using this procedure ..... I am glad I purchased a few extra capsules of ACE's secret 'Pot Lube' before they sold out, I sure do miss ACE R/C as it once was?! Does anyone know exactly what-is this ACE 'Pot Lube' stuff? It looks very much like axle grease to me?

fizzwater2

My Feedback: (61)

The pots in a Proline stick are quite a bit different from those in the ace stick assemblies - the Ace units used a pot like the servo feedback pots of the era, and you could take them apart and clean them. The proline units were a 7/8" diameter high quality unit with a 1/4" shaft, if I remember correctly - at least the ones in my proline custom comp are.

Take a look at the Bourns pot on this link.. the model 6639 single turn pot.

http://www.bourns.com/components.aspx?cmsphid=7631383|7163299|3132787

and see if this isn't close to what you've got in your TX. I used to have some of these, but I've moved a couple of times since then, and they'd be nowhere to be found.

Digikey has the bourns units in stock, 460 of the 5K ohm ones last time I looked. They aren't cheap, 11.46 each.

I'll try to grab a pic of the one I'm thinking of from the digikey website. www.digikey.com you can search for bourns 6639 on the digikey site and find 'em.