[sdiy] Endless Rotary Potentiometers

[Nathanael King]

I'll address everything in one email FSS (for spam's sake :) )

"Have you considered desoldering and removing the pots and then
opening them up and cleaning the contact surfaces?

I've done this enough times to know that, for me at least, the time
and hassle of reconditioning the odd mechanical rarely outweighs
spending a few £€$¥ for nice shiny new ones.

😁


Sent from my Techstar TS-305"

^if I have to desolder, I'm going to replace with new ones. Yet, the
stores are asking $5-8 per. $5 is swallowable, but will be $40 if I
have to replace them all, like I should. In the meantime, I'm going to
keep working with the de-oxit and hope to not have to do any of it.
Desoldering pots sometimes yields the necessity of replacements due to
my *cough* craftsmanship - especially with the high temp solder these
days.

And, hey, I've got a ts-305 too....

"I think these "dual wiper" endless pots are used in the Alesis Ion
too. So might be worth looking for Alesis spares. I heard of Alesis
sticking a replacement pot in the post after someone I know managed to
shear the pot shaft clean off moving their Ion at a gig.

As far as I know the two wipers are 180 degrees apart physically, and
some clever software makes sure the signal is taken from one wiper
when the other wiper leaves the end of the track and jumps back to the
start. Essentially, each wiper is used to cover up the discontinuity
when the other wiper crosses the dead spot on the track."

Thanks, Richie. The ION lead was a great idea. Unfortunately, the body
at least seems different. And the pricing makes it not worth trying to
figure it out. Additionally, they look even more proprietary.
http://www.syntaur.com/2105.html

The other information as far as function is what I found too.

"quadrature encoder"
I don't think that will work. If there were an absolute encoder that
was resistive instead of digital, then that would (should) work
essentially the same way as the pot described. Sounds expensive. I'm
looking for a $2 pot in stock at one of the big four.

Thanks!
Nate

On Tue, May 6, 2014 at 5:51 PM, cheater00 . <cheater00 at gmail.com> wrote:
> Quadrature encoders?
>
> Cheers,
> D.
>
> On 6 May 2014 23:27, "Richie Burnett" <rburnett at richieburnett.co.uk> wrote:
>>
>> I think these "dual wiper" endless pots are used in the Alesis Ion too. So
>> might be worth looking for Alesis spares. I heard of Alesis sticking a
>> replacement pot in the post after someone I know managed to shear the pot
>> shaft clean off moving their Ion at a gig.
>>
>> As far as I know the two wipers are 180 degrees apart physically, and some
>> clever software makes sure the signal is taken from one wiper when the other
>> wiper leaves the end of the track and jumps back to the start. Essentially,
>> each wiper is used to cover up the discontinuity when the other wiper
>> crosses the dead spot on the track.
>>
>> Hope this info helps,
>>
>> -Richie,
>>
>>
>> Sent from my Xperia SP on O2
>>
>> ---- Nathanael King wrote ----
>>
>> >Hi List,
>> >
>> >I'm having trouble finding proper search terms. I just purchased a
>> >bunk mpd24. Seller said "Values are jumping all over the place". I
>> >found 3 problematic pots. I would have thought they would be simple
>> >encoders - silly me. My reading suggests Akai used potentiometers that
>> >rotate a full 360 degrees. They are a 9mm size and standard footprint.
>> >Metal shaft, threaded bushing. There are 4 pins - one for each end and
>> >!2! wipers. People that sell them linked below.
>> >
>> >http://www.mpcstuff.com/1a0-09-0044.html
>>
>> > >http://www.vstservice.com/p-710-akai-mpd24-mpk-control-rotary-potentiometer.aspx
>> >
>> >I'm not interested in paying over $20 for 3 pots (call me crazy).
>> >Anyway, I thought I'd probe the list on the perchance someone has run
>> >across this before and has inside information. They are Alpha brand. I
>> >couldn't find a datasheet for these in the places I looked. Of course,
>> >Alpha will make anything you want in the right quantity, so I don't
>> >really expect much help from them.
>> >
>> >I have used de-oxit and come close to full functionality on some of
>> >the jumpy pots, but one isn't playing nice at all. So, yes, I'm trying
>> >to just clean it in the meantime. It appears someone spilled a sticky
>> >substance (beer) on the unit.
>> >
>> >Thanks,
>> >Nate
>> >Paper Products Music
>> >_______________________________________________
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>> >Synth-diy at dropmix.xs4all.nl
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-- 
Nate King
Paper Products Music