Xpantastic!

Hi everybody,
Can anyone help me ? I've got this voice problem with my Xpander:
on voices 2 and 3, the 2nd VCO doesn't work, and it's NOT the 3374
nor the filters. I've changed them all. I'm starting to think that it
must be some digital control over the analog voices that is failing.
Is there someone who has had this kind of problem? I'll be grateful
for any suggestion.
Thanks to everybody,
Philippe

Hello Phillipe,

Look at the Bypass capacitors "Cx49" that each voice feeds into.
It's toward the front of the board.
C649 = Voice 2
C549 = Voice 3

It's a 2.2 uF. That I have seen fail from time to time. This will 
block signal from getting out of the voice.

If you have an oscilloscope...
1) Turn all voices off but the one you are trying to fix, in the    
   master page.
2) Turn the VCA2 All the way up so it is constantly playing.
3) Look at the signal on the + side of the cap. If you have a     
   waveform signal then the voice is good.
4) Look on the other side of the capacitor, if there is no signal
   Replace The Cap.

5) If you have no signal on the + side of the cap try the output op- 
   amp Ux16 a TLO81
Good Luck and let me know how it goes.
Karl



--- In xpantastic@yahoogroups.com, "philipperyckman" <caractere@...> 
wrote:
>
> Hi everybody,
> Can anyone help me ? I've got this voice problem with my Xpander:
> on voices 2 and 3, the 2nd VCO doesn't work, and it's NOT the 3374
> nor the filters. I've changed them all. I'm starting to think that 
it

> must be some digital control over the analog voices that is failing.
> Is there someone who has had this kind of problem? I'll be grateful
> for any suggestion.
> Thanks to everybody,
> Philippe
>

Hi Karl,

Many thanks for the suggestions. I'll try it tonight and let you know.

Best regards,
Philippe

No, the failures appeared separately.

Thanks,
Philippe