Macgyver Technique to extend stem on Slider Potentiometers

[DrGonz78]

So let's say you have the right type of slider pot but the stem on it is too short. Has anyone made stem extensions before and how did you do it? Also, note that this is not a professional repair at all, but would like something that will last a good time. Kind of a goofy question but someone must have tried something like this before me.

Edit: I had done a search on here and found nothing... Posted this and looked down to see this thread...

http://music-electronics-forum.com/t30437/

[soundguruman]

You take the slider apart and use hardware from another to rebuild it.
For example I have a broken 50K slider, I can order a 5K and use the parts to rebuild the broken 50K one.

I have done this with Marshall pots for mode 4 amps.
Everybody seems to be out of 1 meg PC mount 4 terminal horizontal pots (for mode 4).
But I can take a 5K and use the shaft assembly to rebuild the 1 meg pot. And it works fine.
Takes time and effort, but do-able for sure.

If you are rebuilding controls in this way, I recommend (not only cleaning the resistor track with Caig Deoxit D- 100)
but also coat the contact surfaces with Caig Deoxit G100 before re-assembly.
This will give you what seems to be maximum life span of the surfaces...

For mechanical (not electrical) slide surfaces, between the metal case and the contact mount surface...(not the contact itself)
a small amount of food grade silicon grease will help the parts slide nice and smooth.
You can buy this grease at a scuba store. They use it for lubing zippers on wet suits. It works great for slide faders.

Necessity is the mother of invention. Over the years I have fixed many controls using parts from other faders and pots.
But it's a big investment in time and effort for sure.

[Enzo]

Gasp, I agree. Although I use white lube - a fine grease - for the mechanical surfaces.

I do this for sliders all the time, and even on some rotary pots. Unbend the tabs that hold it all together, carefully take it apart, Use parts from more than one slider to make up a good one.

[DrGonz78]

You take the slider apart and use hardware from another to rebuild it.
For example I have a broken 50K slider, I can order a 5K and use the parts to rebuild the broken 50K one.

Yeah the broken stems are 50k slider pots and all the stem levers are missing completely. So I got a 10k pot from mouser and I did take it apart to use the hardware. That part of this little endeavour I guessed right on and I have a working 50k with the new 10k hardware. Having the PA out for so long I forgot that the stems needed to be like 2 inches long to reach the outer face plate of the console. So I am really now trying to find a way to make extenders for my new pots. I have only put one of these together so far, so this might work or not. Does anyone know where I can find a slider with really long pot stems that have these specs as below pot? Minor details right? lol

Here's the slider pot I used to replace hardware
PTA4544-2010CIB103 Bourns | Mouser

http://www.mouser.com/ds/2/54/pta-69975.pdf

The specs of the slider pots are almost identical to one I am replacing and I think Sunn/Fender must have used Bourns to make the originals.

Everytime I try to imagine some kinda jimmy rig solution to make extenders, I always start thinking it's not a good idea.

[Enzo]

Usually, the slider lever sticks up through the slot, and you stick the knob onto it. But there are slider knobs with a shank that sticks down through the panel. In those cases, you need the slider lever to come just almost to the panel. Look on this Mouser page, second item down, right column.

http://www.mouser.com/catalog/catalogusd/646/2042.pdf


I have used those for this. I needed a very long lever, and failing that, I used shorter ones with these deep reaching knobs. Might work.

[DrGonz78]

Cool, I think I needed the longer metal shaft stem model and order up those knobs too to have around the shop. I did not get the longest stem they had and measuring again I see what will work. I think that they did not have what I needed with the right stems when I ordered, but I will check again. These slider pots have so many dimensions to measure and get right that it is real easy to over look one aspect.

Edit: Oh yeah I see the one that has the metal stem but is was for audio and the one with the plastic stem it the linear one. That's why ended up with the silly short plastic stem model. Got to check Digikey or other places to check for other places, these things are horrible to track down. lol

[DrGonz78]

Of course I dont care if it's audio or linear if I am only using the hardware parts. So I will get the PTA-4544-2015DPA103 and it will work for my purposes as a linear slide pot. Of course after I change out the internal carbon tracked internal board. It's the carbon tracks that make it linear or audio type, right? The wipers are the same regardless?

Edit: Note that I just re-typed PTA-4544-2015DPA103 These things get me confused so easily.

[g1]

Yes the wipers should be the same. Exceptions would be in cases like stereo versus mono fader, where wipers would be different.

[The Dude]

The REAL MacGyver would make extensions out of foil gum wrappers and attach them with bubble gum.

[g1]

I'm with Dude on this. You guys and your professional solutions are not very MacGyver at all .
I was thinking maybe duct tape should be involved or clamping some mini-vice grips to the remaining stub (to be left there permanently). However the gum & foil technique may be more true to the spirit of MacGyvering.

[DrGonz78]

I think looking up the term Jerry Rigging/Jimmy Rigging that the definition should just say Macgyvering.

[Enzo]

And MacGyver's thing would fire like a cannon.