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Vintage Synth Repair

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Arp Avatar -- no sound.

Arp Avatar -- no sound.

2006-10-20 by moremodernmusic

I have an Arp Avatar which has no sonic output whatsoever. it just 
powers on.  I tried connecting to the CV out from an Odessey with no 
results but a faint clicking sound.  I could not even get the LFO to 
oscillate or the S and H to sound off.  Does anyone have any 
suggestions on what to try next?  Could it be the VCA circut or 
something related to the CV or something more simple such as some 
adjustmnet to the guitar control circut.  I appreciate any help.

Re: Arp Avatar -- no sound.

2006-10-20 by John Koumoutseas

Check the Power supply first...same as the Odyssey +-15v. 

--- In vintagesynthrepair@yahoogroups.com, "moremodernmusic" 
<moremodernmusic@...> wrote:
Show quoted textHide quoted text
>
> I have an Arp Avatar which has no sonic output whatsoever. it just 
> powers on.  I tried connecting to the CV out from an Odessey with no 
> results but a faint clicking sound.  I could not even get the LFO to 
> oscillate or the S and H to sound off.  Does anyone have any 
> suggestions on what to try next?  Could it be the VCA circut or 
> something related to the CV or something more simple such as some 
> adjustmnet to the guitar control circut.  I appreciate any help.
>

Re: [vintagesynthrepair] Re: Arp Avatar -- no sound.

2006-10-20 by Mike B

thanks. I just noticed it only makes output throught the External Audio Input on the back of the unit. The output seems to include the routed signal except for the ADSR and VCF. I hope this is a clue -- I am thinking that one of the clips was pulled off one of the boards and put back in reverse. I am not sure if I want to test flipping them.
Thanks!

John Koumoutseas wrote:
Show quoted textHide quoted text
Check the Power supply first...same as the Odyssey +-15v.

--- In vintagesynthrepair@yahoogroups.com, "moremodernmusic"
...> wrote:
>
> I have an Arp Avatar which has no sonic output whatsoever. it just
> powers on. I tried connecting to the CV out from an Odessey with no
> results but a faint clicking sound. I could not even get the LFO to
> oscillate or the S and H to sound off. Does anyone have any
> suggestions on what to try next? Could it be the VCA circut or
> something related to the CV or something more simple such as some
> adjustmnet to the guitar control circut. I appreciate any help.
>


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Re: Arp Avatar -- no sound.

2006-10-25 by easterleggs

Can you get the VCF to self-oscillate using the normal output jack? 
There's one 'master' chip for the VCA (synthfool may have these?).  I
forget the number, but it's a metal can package.  If the VCF is bad
you may need to pull the module and test each component on the
mini-board with a DMM.  I had an Avatar with a bad transistor on the
negative supply rail (VCF module).  I don't have a lot of tech
knowledge, but I brought an Avatar back to life so I can guide you a
bit from experience!

Do you have the wiring schematic to test your theory about the flipped
wiring?  If not, I'll see if I have it for you.

-stephen

--- In vintagesynthrepair@yahoogroups.com, Mike B
<moremodernmusic@...> wrote:
>
> thanks.   I just noticed it only makes output throught the External
Audio Input on the back of the unit.  The output seems to include the
routed signal except for the ADSR and VCF.  I hope this is a clue -- I
am thinking that one of the clips was pulled off one of the boards and
put back in reverse.  I am not sure if I want to test flipping them.  
Show quoted textHide quoted text
>    
>   Thanks!
> 
> John Koumoutseas <john@...> wrote:
>           Check the Power supply first...same as the Odyssey +-15v. 
> 
> --- In vintagesynthrepair@yahoogroups.com, "moremodernmusic" 
> <moremodernmusic@> wrote:
> >
> > I have an Arp Avatar which has no sonic output whatsoever. it just 
> > powers on. I tried connecting to the CV out from an Odessey with no 
> > results but a faint clicking sound. I could not even get the LFO to 
> > oscillate or the S and H to sound off. Does anyone have any 
> > suggestions on what to try next? Could it be the VCA circut or 
> > something related to the CV or something more simple such as some 
> > adjustmnet to the guitar control circut. I appreciate any help.
> >
> 
> 
> 
>          
> 
>  		
> ---------------------------------
> Stay in the know. Pulse on the new Yahoo.com.  Check it out.
>

Re: [vintagesynthrepair] Re: Arp Avatar -- no sound.

2006-10-25 by Mike B

Thanks Stephen,
I could not get the VCF or the LFO to self oscillate throught the output. I was able to check some of the connections using some pictures on-line, but not all pf them. I think your schematic would help and the location of that VCA chip. I appreciate your help.

easterleggs wrote:
Show quoted textHide quoted text
Can you get the VCF to self-oscillate using the normal output jack?
There's one 'master' chip for the VCA (synthfool may have these?). I
forget the number, but it's a metal can package. If the VCF is bad
you may need to pull the module and test each component on the
mini-board with a DMM. I had an Avatar with a bad transistor on the
negative supply rail (VCF module). I don't have a lot of tech
knowledge, but I brought an Avatar back to life so I can guide you a
bit from experience!

Do you have the wiring schematic to test your theory about the flipped
wiring? If not, I'll see if I have it for you.

-stephen

--- In vintagesynthrepair@yahoogroups.com, Mike B
...> wrote:
>
> thanks. I just noticed it only makes output throught the External
Audio Input on the back of the unit. The output seems to include the
routed signal except for the ADSR and VCF. I hope this is a clue -- I
am thinking that one of the clips was pulled off one of the boards and
put back in reverse. I am not sure if I want to test flipping them.
>
> Thanks!
>
> John Koumoutseas wrote:
> Check the Power supply first...same as the Odyssey +-15v.
>
> --- In vintagesynthrepair@yahoogroups.com, "moremodernmusic"
> > wrote:
> >
> > I have an Arp Avatar which has no sonic output whatsoever. it just
> > powers on. I tried connecting to the CV out from an Odessey with no
> > results but a faint clicking sound. I could not even get the LFO to
> > oscillate or the S and H to sound off. Does anyone have any
> > suggestions on what to try next? Could it be the VCA circut or
> > something related to the CV or something more simple such as some
> > adjustmnet to the guitar control circut. I appreciate any help.
> >
>
>
>
>
>
>
> ---------------------------------
> Stay in the know. Pulse on the new Yahoo.com. Check it out.
>


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