thread: MS-20 problems
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Old 4th September 2018
  #16
Here for the gear
 

Hi,

thanks to this thread I could fix my MS-20. I had a problem with infinite notes using EG2 so I could only use the synth with EG1 patched. I checked all the potentiometers of EG2 and they were displaying the right resistance values.

Closed to the EG2 pots there are three 14 pin IC, one 4069 (IC-23) and two 4007 (IC-19 and IC-22). I changed the three of them, testing after each one, but only the last one I soldered fixed the problem. It was IC-22, so 4007 in my case, but I recommend getting some replacement of both as I've read 4069 is often the faulty one as well.

I got the parts from Syntaur, and luckily they were not too expensive :

4007 : IC, 4007 dual FET/inverter
4069 : IC, 4069 hex inverter

hope this helps someone and thanks to the people posting here, I had a place where to start.