the Korg35 mystery show

[Martin Czech]

I tryed to find out more about the infamous KORG35 module that makes
up the core for the VCFs in the early Korg MS20 synths. The repair tech
at Korg Germany confirmed to me, that NO schematics where handed out by
KORG ever, it is just a "black box" for the repair man.

(Funny, this guy's name is "Totenbier" , dead man beer, whoa.)

I also contacted Korg U.K. Very friendly, but also no clue about KORG35,
*but* they send me a module for *free*. Got it yesterday, 10cmx10cmx10cm
box for a 2cm*2cm*0.3cm module ... :->


So at least I got one now. To me it looks like a substrate with some
SMD things (9 bubles, 9 components?) on it, then coated with expoxy or
something.  So it is not really potted epoxy. But I think there where
no SMD parts at that time. Right?

Now I plan: Build J. Haibles latest circuit proposal and the original
circuit.  Hear them side by side, look at waveforms etc.  If there is
no difference (as Juergen allready said), well that's it.

Almost. I'm the kind of curious guy that allways wanted to know what is
inside the alarm clock, driving parents and other people mad...

What else can I do? I could persuade the defect dep. guys to do an X-ray
analysis. It should be possible to see the PCB lanes, if there are any,
and also the components legs. 

As a last step I could try to depoxy. What solvent will I need?
Any hints?

Well, I could ask some Chemist I know...

I've got another request running in the USA/Japan, let's see what comes out.

Below you will find a another mail that KORG Japan send me to my request,
yes, they really did answer! No information will be disclosed :-<.
Maybe they don't have any left!

----- Begin Included Message -----

>From webmaster at korg.co.jp Wed Jun  2 03:51 MET 1999
X-Sender: webmaster at korg.co.jp
X-Mailer: Macintosh Eudora Pro Version 4.0.1J
To: "Martin Czech" <martin.czech at intermetall.de>
From: WEBMASTER <webmaster at korg.co.jp>
Subject: Re: Korg35 device in Korg MS20 synthesizer
X-Lines: 10
Content-Type: text
Content-Length: 253

Dear Martin Czech,


Thank you for your inquiry about the MS20. We are sorry to inform you but we
do not release the information of the IC Korg35 in public.

We hope you will play our legendary Synthesizers with your pleasure.

Best regards,
Webmaster



----- End Included Message -----

m.c.