Author Topic: Salvage Helipot and Duodial RB clean/lube?  (Read 2447 times)

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Offline Trey

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Salvage Helipot and Duodial RB clean/lube?
« on: March 04, 2015, 08:24:12 pm »
I was fortunate (foolish?) enough to buy a sizable lot of salvage Beckman Helipot multi-turn potentiometers (mostly Model A 20K L.25 and Model C 20K L.5) and Duodial RB 14-turn counting dials (from "that" online site). I've desoldered the cut leads from a few and they test out OK on my Fluke, but they are kinda grungy. The dials feel like they could use some lubrication (after a deep cleaning).

Any advice on how to proceed and what to do, not do?

Many thanks!

[edit: changed "used" to "salvage"]
« Last Edit: March 04, 2015, 10:22:34 pm by Trey »
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Offline lowimpedance

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Re: Salvage Helipot and Duodial RB clean/lube?
« Reply #1 on: March 04, 2015, 10:51:48 pm »
If you have a few of the dials try taking one apart.
Since I have quite a few I did just that!. So you will need circlip pliers to remove the first clip, then the dial (knob) will come away from the body. Leave the dial brake clip, should not be required to go that far. Tip ; After taking the clip off make sure the dial is facing up when you remove it so the plastic lever and cog are still on there shafts and you will see how they function !.
 There's not much to it and you should be able to give it a good clean and light lube before re assembling.

Not sure I would be trying to take the pots apart though. Careful clean the outside and perhaps some light lubrication of the shaft bearing to see if that improves.
They should move nice and free allowing you to 'feel' the wiper on the WW track.
Very nice old pots even if they are huge by modern standards!. I have a box load with dials that I just cant throw away.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline Trey

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Re: Salvage Helipot and Duodial RB clean/lube?
« Reply #2 on: March 05, 2015, 08:28:45 pm »
Thanks. I managed to get the first clip off of one dial with improvised tools (and safety glasses!) and was able to clean more deeply.  That, and a bit of light lubrication (I had some RemOil at hand) and it is quite smooth now. As I have 57 more to go, I think I best obtain the proper pliers for the rest.

For the pots themselves, I'll stay outside. I read elsewhere about people taking them apart, but that seems a bit chancy. They are nice pots (and manly looking), especially after a cleaning.

cheers
A problem well-understood is a problem half-solved.
The most important tool in your toolbox is your brain.
KC3BSY
 

Offline Trey

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Re: Salvage Helipot and Duodial RB clean/lube?
« Reply #3 on: March 09, 2015, 03:09:42 pm »
Here are a couple of photos for anyone interested in what these look like.
« Last Edit: March 09, 2015, 03:18:28 pm by Trey »
A problem well-understood is a problem half-solved.
The most important tool in your toolbox is your brain.
KC3BSY
 

Offline uoficowboy

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Re: Salvage Helipot and Duodial RB clean/lube?
« Reply #4 on: March 09, 2015, 03:19:53 pm »
I have had a lot of success with cleaning old Bourns 10 turn pots. They have a metal clip that comes off and then the back pops off quite easily. I then use a little bit of deoxit and a q-tip to scrub away the nastiness, clean that out with IPA, and then add a bit of deoxit gold to lubricate the contacts. Takes 5 minutes and is very effective.

I imagine a similar process would work for your pots if you can figure out how to open them non destructively.
 


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