Crumar Musical Instruments User Group.

> I have two Crumar Bit One keyboards that have bad voices. One has
> three working voices, and the other has a single working voice. 

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? 

> I do have schematics and board layouts, but have not been able to 
> get anywhere with them.

Do you have schematics for both versions?

> I do have a few spare filters of each type, but it appears that the
> problems with these are not the filters, since no matter how I swap
> and change them around, the bad voices are always in the same place,
> such as 1,5,6

At least that means the expensive bits are OK...

> Any suggestions or insights would be appreciated, in particular, what
> sorts of parts are likely to fail on these instruments. These were
> unused for over a year, due to these problems, only more voices have
> failed as time has gone on. I would very much like to get at least
> one of these working again.

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.


Steve