Strange ms20 fault

sam · Post by **sam** » Tue Sep 11, 2007 3:29 pm

Both vco's are playing (low level) when the osc levels are off.

So I have replaced..Caps and regulators on the power board.

Checked all the opamps ect.

Connections/pots ect.

Just cannot find out why...

neandrewthal · Post by **neandrewthal** » Tue Sep 11, 2007 4:41 pm

How "low level" are we talking? Mine does it too, but very slightly so I imagine it's just a little cross-talk and not a fault.

sam · Post by **sam** » Tue Sep 11, 2007 4:55 pm

It's high enough to play ...It's affecting the osc tuning ect.

If either osc is on then the other is heard.

Dammmm wierd.

sam · Post by **sam** » Tue Sep 11, 2007 5:16 pm

Here are the schematics for some korgs..

http://www.korganalogue.net/korgms/mssermans.html

sam · Post by **sam** » Wed Sep 12, 2007 1:40 pm

I have noticed I get a reading of -5v o j24..The schems state -15.

Maybe it's the accepted bleedthrough plus noise that's confusing me.

sam · Post by **sam** » Wed Sep 12, 2007 3:31 pm

I think it's that both osc are not tracking the keyboard in sync..So it's something with the tracking/tuning circuit.

I have also adjusted with my meter the tracking as described in the schems.

So one of the osc is unstable..?

Or maybe a fault on the patchbay..? CV..?

Any pointers...