The Kawai & Teisco Analog Synths Group

Hello group.

First, this is a great knowledge base. I read nearly all of the post.
But it seems that my problem is slightly different.

When I play some sound, one oscillator stucks with the note until it 
is retriggered by another.
i.e. I play c-d-e-f-g the g stucks - keeps on sounding regardless 
what the ENV looks like - then I play futher on a-b-c-d-e and the e 
stucks again,releasing the prior stuck g.
Do you know what I mean?

I did not open the SX210 so far to check the battery.
Any healing far-distance diagnostics?

Cheers, mike