Sequential circuits samplers

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.
>
>
>
>