[sdiy] Matrix 1000 problem (one voice too bright)

[Andre Majorel]

Hi All. I just purchased a Matrix 1000 and it has a problem. One
of the voices is abnormally bright. It's very obvious on patch
#297:

  http://www.teaser.fr/~amajorel/misc/m1000bug.mp3

It occurs every sixth note, starting from the third. It sounds as
if the cutoff frequency was stuck to the maximum. Or maybe
something in the waveshaping. I'm not familiar enough with the CEM
3396 to know for sure.

I've reseated everything that could be. It's not the CEM 3396
(tried swapping them, and the problem stays with the third voice).
I suspect that one of the channels on one of the 4051s might be
dead. I'll pull out the scope and dig into the schematics tonight,
but if you have any advice or ideas, I'd love to hear them.

-- 
André Majorel <amajorel at teaser.fr>
http://www.teaser.fr/~amajorel/