Korg MS-20 oscillator problem

antilles · Post by **antilles** » Mon Dec 11, 2006 7:59 am

The second oscillator on my MS-20 drifts. And when I say drifts, I don't mean after a few minutes. The pitch is in constant motion! Is there any way to repair an osc? Is it possible to buy a new chip or something?

Post by **Maschinengeist** » Mon Dec 11, 2006 3:47 pm

Either the trimpots need a little adjustment or they need to be replaced. The MS20 uses 10k/100k trimpots, depending it's pitch or scale. Replacing or adjusting the trimpots requires calibration been done with an oscilloscope and/or guitar tuner.

Post by **nathanscribe** » Mon Dec 11, 2006 5:12 pm

There's nothing in the MS20 oscs that can't be replaced, i think. They're mostly discrete, with a couple of opamps but only standard ones. Pennies only if the keel over. Now finding the problem is the tough bit.

Bitexion · Post by **Bitexion** » Mon Dec 11, 2006 11:20 pm

You're sure it's not being slightly modulated by the LFO?

antilles · Post by **antilles** » Tue Dec 12, 2006 7:23 am

Bitexion wrote:You're sure it's not being slightly modulated by the LFO?

I'm sure!

neandrewthal · Post by **neandrewthal** » Tue Dec 12, 2006 7:35 pm

antilles wrote:
Bitexion wrote:You're sure it's not being slightly modulated by the LFO?
I'm sure!

That's why I thought mine was broken when I first got it.

When the poor thing has been banged around in a box for a week you jump to conclusions before figuring out what all the knobs do.

Anaki_Muon · Post by **Anaki_Muon** » Mon Dec 18, 2006 8:27 am

Agreed. When I first got my MS-20 I often thought something may have been wrong with it that I had overlooked, but then I would realize I just needed to tweak one or two knobs in the right way! I would think that questions of this nature for any modular or sem-modular should include a picture that clearly shows the settings, as that way you can be sure you're not overlooking anything (not to say you are in this case)!

antilles · Post by **antilles** » Mon Dec 18, 2006 9:57 am

Nope. All settings are at zero. Also it's only osc 2 that drifts. And believe me, it doesn't sound like any modulation. It sounds like a drift!

I'm gonna clean it, and then calibrate it and see what happens.

blackmix · Post by **blackmix** » Mon Apr 18, 2022 10:12 am

Hi, i am having the exact same issue. Do you fixed it? how?

Korg MS-20 oscillator problem

Re: Korg MS-20 oscillator problem