Sequential circuits samplers

The problem is the follow:

When play up to seventh note of the synth, this works good, but when I
play the eighth note this do not responding. An example, to play 7
time the same note in the synth, when you touch the eighth, the synth
keeps in silence.

This problem is very stranger, but I have seen it in other synths like
ensoniq.

someone have had this problem before?
Which is the solution for this ?

The Prophet 2000 is big synth/sampler with analog filters, so I want
to repair it, for continue enjoying with the special and unique sound.

Thanks

sounds like a dead curtis voice chip. you could try wine country for a
replacement or watch for someone here who's breaking a machine for parts. 

I will soon have to decide what to do with my 2000- the kybd
controller IC has failed & can't be replaced, so I will keep some bits
as spares for my 2002 & sell the rest.

duncan.

I had this exact problem on mine except it was voice number 7. I tried swapping all the voice chips out against a new one I have and with all the others but the problem remained. It still remains unsolved. 

The last time I looked at it the unit didn't even power up to make any noise which I'm 98% sure is down to the PSU caps dying of age (and I'm hoping and praying nothing has been fried in the process) . I haven't had any time to look at it again since. 

Sorry its not a huge amount of help but it might help you or save you some cash getting replacement chips you don't need if you can try changing them to start with. Good luck.

Best regards, Martin
   

--- On Fri, 28/11/08, duncan <ferrograph@...> wrote:

From: duncan <ferrograph@...>
Subject: [prophet2000] Re: Problem with eighth voice
To: prophet2000@yahoogroups.com
Date: Friday, 28 November, 2008, 1:49 PM










    
            sounds like a dead curtis voice chip. you could try wine country for a

replacement or watch for someone here who's breaking a machine for parts. 



I will soon have to decide what to do with my 2000- the kybd

controller IC has failed & can't be replaced, so I will keep some bits

as spares for my 2002 & sell the rest.



duncan.

Logic ICs are suspicious among aged instruments too; voice  
distribution might fail if one of the voice addressing destinations  
can't be activated by some faulty CMOS.. AFAIR there're plenty of HEX  
flipflops (40174?) in the voice board circuit, maybe the dead voice  
doesn't flip (or flop;)) any more.


r.

On 28.11.2008, at 17:42, Martin Selwood wrote:

> I had this exact problem on mine except it was voice number 7. I  
> tried swapping all the voice chips out against a new one I have and  
> with all the others but the problem remained. It still remains  
> unsolved.
>
> The last time I looked at it the unit didn't even power up to make  
> any noise which I'm 98% sure is down to the PSU caps dying of age  
> (and I'm hoping and praying nothing has been fried in the  
> process) . I haven't had any time to look at it again since.
>
> Sorry its not a huge amount of help but it might help you or save  
> you some cash getting replacement chips you don't need if you can  
> try changing them to start with. Good luck.
>
> Best regards, Martin
>
>
> --- On Fri, 28/11/08, duncan <ferrograph@...> wrote:
> From: duncan <ferrograph@...>
> Subject: [prophet2000] Re: Problem with eighth voice
> To: prophet2000@yahoogroups.com
> Date: Friday, 28 November, 2008, 1:49 PM
>
> sounds like a dead curtis voice chip. you could try wine country for a
> replacement or watch for someone here who's breaking a machine for  
> parts.
>
> I will soon have to decide what to do with my 2000- the kybd
> controller IC has failed & can't be replaced, so I will keep some bits
> as spares for my 2002 & sell the rest.
>
> duncan.
>
>
>
>