Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

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Subject: Re: [PolySix] RE: Polysix tuning difficulties.

From: Bob Grieb <bobgrieb@yahoo.com>
Date: 2014-02-28

Hi,

    The voltage at TP2, called Oct/V CV, which seems to be the input
to the antilog ckt, is constantly switching between 8 values.   Six of them
are the same when you go into unison mode, but there are still two other
ones being muxed in.    I guess for the factory calibration they must have had
a way to pause the muxing and put out specific DAC values for setting the
trimmers using a DMM.  Seems like that code would be in the keyboard
MCU, unless they had a factory test MCU that they used.

Bob
 


From: Malte Rogacki <gacki@gacki.sax.de>
To: PolySix@yahoogroups.com
Sent: Friday, February 28, 2014 3:54 PM
Subject: RE: [PolySix] RE: Polysix tuning difficulties.

 
Does anyone have access to a complete (!) Trident Mk II service manual?
Posting the procedure for the antilog calibration would help tremendously.

I have the calibration routines for:

Trident (Mk I) -> incorrect and partly implausible
Poly-61 -> will have to check
MonoPoly -> will have to check

Can anyone think of other Korg Polysynths from that era that might use the
same antilog technique? I think this is the list:

Polysix
Poly-61
MonoPoly
Trident
Trident Mk II

It would seem odd to me that all of them have an antilog calibration
routine except the Polysix. The Polysix also has a test point at the same
circuit position...