removing jitter from 1m ohm pots.

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I here a few had some success just cleaning with alcohol. Here is a guide most people follow.

http://www.atariguide.com/help/c...

For me I find this never helps. IMO, its easier just to replace the pot but this wont work for my target audience. Anyone have another method for removing jitter?

I gave up doing it in code, just no balance between the jitter and human signatures.

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I assume that you refer to 1megohm pots, not 1 milliohm pots?

I cannot say that I have ever had "jitter" from a pot. Noise, maybe. Must you use pots with such a high value?

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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Right 1megohm. The pot is part of the device I'm interfacing with.

Sorry, I neglected to say its not being used as a pot but more so a variable resistor. Where the middle lead is absent.

Just wondering if there are other means of correcting the jitter. These devices are 30 some years old.

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I am almost twice that age and alcohol certainly works well.

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The jitter then probably is due to the fact that the contacts either are worn off, or a lot of dirt has build-up on the contacts. In the first case alcohol will probably help a very short time as the contacts are cleaned and some contact is restored, but after a while it will start failing again.
ON the second the alcohol should work and clean the contacts. dont forget to move the pot meter a while from min to max and back to clean the contacts of more resistant dirt.
but after 30years... the chane is big that the pots are worn and might need replacement. specially if they are used in s very limited range and a lot of the time. Perhaps check the datasheet if available and see how many wipes are guaranteed or years and do a bit of math on the usage...

regards

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ignoramus wrote:
I am almost twice that age and alcohol certainly works well.

btw I think we did not wanted to hear that....
and how long does the alcohol work for you??? long term of short term only ;)

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Admit that - changing the pot is the best, for sure. Such pots are still available I believe. Target audience will not notice the swap. That's because not only the contacts are worn - this also valid for collar. Old pots do have loose axle, too.
The next option is to use special spray or grease for better contact. These usually contain graphite or alike. Helps with noise at both the slider and axial contact. Copper or bronze foil will restore the bearing.
Would stick with replacement so.

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well the issue is that the replacement is not keyed.

the pot poll is () not (| . With these devices you either a have to file down the poll some how, or make the counter part a circle and not a half circle.

If I could find a pot with the appropriate notch, then I'm good.

He is a write up on what need to be done
http://www.vintagegamingandmore....

--You know I never though about this before, but I would think all I need is the pot inners?

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Quote:

and how long does the alcohol work for you??? long term of short term only

Ummm--I forget. :twisted:

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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That poll is bronze or alike. Easy to shape with file: just fix the poll in wise.
I would think also swapping resistive horseshoe board - more assembling work but less cutting and grinding. Doable, used to restore pots like that in last century.

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Here is a suggestion from left field. Apart from any slippage problems in the shaft (your "poll"), you could add a 2.2megohm resistor in parallel with your pot. That will have the effect of moving your active areas of use slightly and maybe into an unworn area of the resistive element (the horseshoe).

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia