Dual pot shafts stuck

Mike Sweeney

AK Subscriber
Subscriber
My 2226B has three pots ( treble, mid, bass that are doubles with an inner and outer shaft. They are very, very stiff and resistant to a gentle treatment of cleaner/lube down the shaft. I have not found any real info on a way to "un-stick" them. My guess is the only real way is to unsolder them and then physically take the cans apart so I can take the shafts apart and clean/polish/lube them. Not really looking forward to that without some donors available :) Does anyone have a better solution or idea? Thanks
 
My 2226B has three pots ( treble, mid, bass that are doubles with an inner and outer shaft. They are very, very stiff and resistant to a gentle treatment of cleaner/lube down the shaft. I have not found any real info on a way to "un-stick" them. My guess is the only real way is to unsolder them and then physically take the cans apart so I can take the shafts apart and clean/polish/lube them. Not really looking forward to that without some donors available :) Does anyone have a better solution or idea? Thanks
Can you get a hair dryer in there to heat and gently work it.
 
Welcome to AK, spraying down the shaft does very little to clean the pots. You must use the correct cleaner (most here use de-oxit) and you need to remove the covers (bottom and top) and locate the small opening on the pots (dual shafts will have dual pots) and spray the de-oxit directly into that opening, then work the controls. This may take more than one application but is much easier than dis-assembly of the pots. Switches also have a small hole that you can inject cleaner into which also helps their operation. Sliders require special cleaner (fader lube) and even when using the correct cleaner, rarely operate as they did new. Good luck! Rich
 
Welcome to AK, spraying down the shaft does very little to clean the pots. You must use the correct cleaner (most here use de-oxit) and you need to remove the covers (bottom and top) and locate the small opening on the pots (dual shafts will have dual pots) and spray the de-oxit directly into that opening, then work the controls. This may take more than one application but is much easier than dis-assembly of the pots. Switches also have a small hole that you can inject cleaner into which also helps their operation. Sliders require special cleaner (fader lube) and even when using the correct cleaner, rarely operate as they did new. Good luck! Rich

I dont think I made myself very clear. I'm well acquainted with DeOxIt.. I've been restoring tube sets and amps for 15 years or better now. The adventures in restoring my Marantz solid sate stuff is relatively new to me. It's not the pot resistor elements that need cleaning, it is the shafts themselves. The outer shell and the inner shaft are binding on each other then you try to turn them independently, like when you want more mid tone from the left side vs the right side.

The post picture is not the exact pots but they show the double shafts with the inner and outer.
 

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If they turn easily together, then it isn’t in the cans. Hard to figure why solvent wouldn’t free up the two shafts from one another unless something was bent.:dunno:
 
The ones that I fixed were so stuck that you could not move them without considerable force. I thought the knob would strip the shaft of the pot. I tried all kinds of stuff... Every spray you can think of and heating the crap out of it. Nothing worked. I even took one apart, in the process I ruined it.

If you have a pin vice and small drill bit you might be able to do it by hand and leave the pot installed. You will need to drill far enough to make it to the inner shaft. All you really need is a pin hole. Putting the pot in a vice and using a press makes it easy, and you can clean it.
 
The pin vise is a very good idea. I have a set of those and the bits to go with it. Sounds like a time for a cigar while slowly drilling the pots :)
 
So on my "new" 1030, the tone pots are the same stuck pots as my 2226B. Except they are single shaft vs dual shaft. The commonality between them is the use of brass outer sleeve and an aluminum shaft. The AL to AL are not sticking at all. The two tone controls have the brass/AL combo. And both were stuck like harden tar. I was able recover them to pretty much normal effort. It took my paint stripper heat gun, some electronic lube and some DeOxit.. and about 45 mins per pot. I tried just socking the shaft with lube over night. None starter.. no change. Then I got out the heat gun and got one pot's shaft hot, not warm, hot. Moved easily while hot but stiffened right back up as it cooled. Heated it again and hit with some of the spray oil.. worked it in as it cool. It went stiff but not quite as bad. Heated it to where I could see the oil start to push some black crud out of the tiny gap between the brass and AL shaft. Hit it with a generous amount of DeOxit and worked that down the shaft by rotating and push/pull the shaft. That did wonders but not fully. Heat it one last time to where some black crud came out ( only to where it slightly came up) and hit again with DeOxit and worked it then let it sit overnight. That pot now rotates just like it should with the incremental bumps and with just two fingers of effort. I plan to hit tonight with some lube then clean the pot's contacts. That leaves one more pot to do :) The second one was never as stiff as this one but it's still stiffer than what it should be. I don't know what Marantz ( or the pot vendor) used for lube but it's nasty crap.
 
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