Kenji,
I have the full service manual for the GX-1. If you need them, I can send
you the schematics for the KAS.
I designed a MIDI-enabled replacement KAS. Take a look here:
http://www.sequentix.com/gx1/I have the two original KAS boards taken from the GX I designed the MIDI
retrofit for.
If you are not interested in adding MIDI, and it turns out you have any
failed (and unobtainable) Yamaha ICs, I could ask the owner if he might sell
them.
I also have a MIDI-enabled Tone Board replacement for solid-state patch
storage and MIDI editing that is just about finished.
Your description of 2 octaves out of 5 being correct suggests a failed 4051,
IC19.
That is the analogue switch that selects the octave reference for the
semitone DAC.
Best regards,
Colin Fraser
Sequentix Music Systems Ltd
http://www.sequentix.com > -----Original Message-----
> From: yamahacs80@yahoogroups.com
> [mailto:yamahacs80@yahoogroups.com] On Behalf Of kiucd
> Sent: 30 October 2009 18:03
> To: yamahacs80@yahoogroups.com
> Subject: [yamahacs80] Need help on KAS board for GX-1
>
> hello
> I need help for my GX-1.
> both of KAS boards for upper and lower
> keyboards have problem and now my GX-1 can not sound correct.
>
> upper key keeps silence.
> lower key, two octaves out of 5 sound correct, however the
> others sound silence or strange.
>
> YAMAHA here in JAPAN gave up to fix them already and my
> friend in sweden does not have time to help me.
>
> sorry to bother this message board since it is for CS80.
> I hope to hear from some analogue synthe lovers......
>
> sincerely
>
> Kenji
> YOKOHAMA city, JAPAN
>
>
>
>
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