Vintage Synth Repair

-----Mensaje original-----
De: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com]En nombre de francois basquin
Enviado el: miércoles, 21 de marzo de 2007 19:02
Para: vintagesynthrepair@yahoogroups.com
Asunto: RE: [vintagesynthrepair] Problem with Kawai SX-240.

Joan, do you have the schematics of this part ?

>From: "Joan" <piniflopa@terra.es>
>Reply-To: vintagesynthrepair@yahoogroups.com
>To: vintagesynthrepair@yahoogroups.com
>Subject: [vintagesynthrepair] Problem with Kawai SX-240.
>Date: Tue, 20 Mar 2007 18:41:49 -0000
>
>Hello,
>
>I bought some time ago this synth with a lot of problem that I've been
>fixing. But now I don't know how to solve the remaining problem.
>
>I found the problem in cutoff voltage control from D/A converter. It
>looks in some of the 8 stages the voltage is right (1st, 2nd,3th and
>5th) but in other is not possible to adjust the Voltage in the SSM
>filters. I also swap two chips just in case and afortunately the
>SSM2044 are ok. I change the circuit multiplexer and the IC's that
>provides de D/A conversion throght the R-Array. Some of the wrong
>stages are just impossible to adjust, other are noisy. My thinking is
>that the switching time is delayed between CPU and multiplexer but as
>I cannot chceck with osciloscope -I don't get one- I'm just sttoped in
>that situation.
>The system (apart from SSM chips) is quite similar to JUNO's. Does
>anayone get a similar problem? Or more important does anyone know thow
>fix it?
>
>Many thanks in advance.
>
>Joan M.
>www.soundclick.com/nolabelavailable
>

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