[sdiy] A part for a CS20M
synthnerd at eircom.net
Mon Jul 1 23:49:55 CEST 2013
Thanks for the replies,
Steve's explanation summed it up very well, and it does run on +5V and
-10V. It would take quite a bit of CMOS logic to achieve this function.
Interestingly enough, the memory preset LED section is one part of the
synth where using the YM617 is unnecessary, and Yamaha used a lot of
extra circuitry to turn the outputs of the 617 into something to drive
LED's. Ironically this is a cosmetic issue, the switches function
correctly and call up presets as expected. If any other YM617 had
failed, the synth would be unusable (lucky escape for the client).
I got the CS20M service manual quite easily on-line, maybe it was from
manuals.fdiskc.com/flat there is no clue from the manual itself.
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