Crumar Musical Instruments User Group.

> Which one (2044 or 3328) has the three working voices?  
> Is it all the upper or lower voices that have failed, or a random 
> selection? 

Hmmm... Now I can't remember - I'll have to hook them up again to be
sure but I think the one with only one good voice was the one with
3328s.  The voices that have failed are very specific to the note
order.  If I press one key and keep it held down, then press another,
etc... I can determine how many voices of the six are working.  They
are always dead in the same order, such as: 

1-quiet, 2-working, 3-working, 4-working, 5-quiet, 6-quiet

or 

1-quiet, 2-quiet, 3-quiet, 4-quiet, 5-working, 6-quiet

> > I do have schematics and board layouts, but have not been able to 
> > get anywhere with them.
> 
> Do you have schematics for both versions?

Unfortunately, I only have schematics for one version - but since I
can't find anyone in the state that fixes vintage keyboards, I'm kind
of stuck.  My ability to read schematics is quite basic.  I can find a
component in the diagram, then find the actual part on the board, but
that is about it.  Knowing what part may be responsible for the
problem is beyond me.

I got a basic oscilloscope expecting to be able to read the output
from each signal pin of the ICs in each circuit path, assuming that
one of them would be suspiciously flat-lined - but I haven't found
anything like that in poking around so far.  Everything seems to have
power and is moving signals along.
 
> If you open the noise slider, do any of the dead voices pass/filter
> the noise?  That might give you a clue if it's the DCOs or later in 
> the signal path.

I'll have to give that a try, although from what I recall, the noise
was audible.  I'll write again as soon as I get them tested again.  

Thanks very much for your consideration!!