KORG M1 broken master volume slider

Dorchester · Post by **Dorchester** » Wed Nov 09, 2005 5:47 am

Hallo,
This is my first day here. I would like to ask all of you a question. I need the exact parameters of this slider, so I can buy one or a replacement here in Bulgaria. But I do not know where to find the specifications.
Please, help and thanks in advance.

<font size=-1>[ This Message was edited by: Dorchester on 2005-11-09 06:35 ]</font>

Zer · Post by **Zer** » Wed Nov 09, 2005 6:20 am

Probably you would like to have a look for moogulator. http://www.synthesizerforum.de

He´s the author of http://www.sequencer.de

And in his forum you´ll meet very kind synth technicians.

paulrmartin · Post by **paulrmartin** » Wed Nov 09, 2005 4:21 pm

http://www.korgparts.com/

astroman · Post by **astroman** » Wed Nov 09, 2005 7:37 pm

the specs are printed on the slider

a number,
a unit (Kilo Ohm or Mega Ohm) abreviated K/M plus (often) the greek Omega letter
the type of resistor (if it's value changes linear or logarithmic) lin/log

to replace it, you'll have to open the box anyway - not exactly fun on the M1 according to what I've heard

oops - it's the volume, not the value slider... that part is totally uncritical, you do not need to match the exact specs, just the range.

btw it reminds me: does the slider make noise or doesn't it work anymore ?
if it's the latter, it may not be the slider itself, but a parallel capacitor that leaks and shortens signal to ground.

good luck, Tom

<font size=-1>[ This Message was edited by: astroman on 2005-11-09 19:51 ]</font>

Dorchester · Post by **Dorchester** » Thu Nov 10, 2005 1:05 am

Thank you all!
The slider works half way up, then the sound stops, then when the slider reaches the top, the maximum sound appears. The slider makes no noises.
Opening is no problem, but I'm almost sure that in my country I won't find one spare part for the Korg M1! That is why I'm looking for a replacement. Tonight I will have a look and read the specs (inside) and try finding it in the Internet. The way I purchase them, anyway, is totally indistinct.

P.S. Hope you understand my English...

astroman · Post by **astroman** » Thu Nov 10, 2005 3:23 am

On 2005-11-10 01:05, Dorchester wrote:
...but I'm almost sure that in my country I won't find one spare part for the Korg M1! That is why I'm looking for a replacement. ...

exactly - such a slider is more likely to be found in hifi, TV, old cassette or reel-to-reel recorders.

Fortunately there are not too many mechanical variations - 60 and 100mm the most common.
The thing is called potentiometer, it's a resistor along a linear path with a moving middle connector.
In your case slider position defines the effective lenght (=value) of the resisor.
Looks like one half of is broken off, so there's the gap and at the endpoint it gets connection again.
It's a simple thing, dont worry

While you're at it you might want to replace any buttons if you experience that you have to push them several times before they react.
you can use (desolder) them from almost any electronic gear, the switches are very common parts.

cheers, Tom

valis · Post by **valis** » Thu Nov 10, 2005 11:23 am

Are you sure its not just VERY dirty? I would try some compressed air then a bit of CAIG 5% deoxit or something similar. Also on my older synths due to dirty sliders I leave volume at max and use either midi or external mixer to attenuate.