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

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Subject: new members = old questions (+ proposal for the future this site)

From: "koookaburra" <koookaburra@yahoo.fr>
Date: 2005-03-31

∗∗∗∗ A great hail! to the community from South of France :-) I've
been gathering tons of useful tips about the polysix on the web and
I've decided to purchase one which needs a fix (battery leakage). [
BTW I can provide you a personal webstorage to host a site and a forum
(mysql) for free and without advertisement. The Polysix deserves it
and you guys deserve it too ! So if the moderator of this mailing-list
is interested he can contact me anytime… ]∗∗∗∗


∗ Things that I've already done :

- Replacement of 4011 (x2) 4048 (x2) 74LS08 (x2), 4051 (x1), TL072
(x1) chips : I'm lucky for they were socket'ed and not soldered.
- Continuity test of the whole board (I think I should maybe
double-check but I've no schematics of the whole board, only the
battery area)
- Resoldering few tracks

∗ Things I've noticed :

- Non-working functions :
VCF : Cutoff – EG Intensity – KBD Track
MG : Frequency – Delay Level – MOD switch (VCO, VCA, VCF)
– MG led
doesn't light up
(As I've no experience of the P6 I can't tell if the
Resonnance is ok : it sounds a bit harsh to me)

- It requires a warm-up usually 10 seconds (and sometimes 5 minutes)
before the whole lights turns back to normal (during the warm-up they
are all lighted-up)

- Sometimes the sound gets distorted while I'm playing, or the
volume decreases suddenly and then turns back to normal. Usually after
a 15-30 minutes test the synth does not want to play anymore or acts
too weird to continue the test.

∗ Questions I'm asking :

- Does the continuity test (with a multimeter) is an accurate way to
check if the circuits are ok ? `Cause I've noticed several soldering
holes which look strange and I'm suspicious about them (see picture
here : http://16days.free.fr/Polysix/P6-1.jpg ). On the other hand
when I test the tracks between two of these holes the multimeter
buzzes normaly…

- Anyway is it possible to get an accurate diagnostic as long as
I've not resoldered a new battery ?

- I was wondering about the capacitors : do you think I could be a
cause of the malfunctions ?

- Is there a specific area on the board involved in the Cutoff and MG
functions ?

- I've several NEC 8084C chips and I wonder if I can replace the
original one by one of those. Or does it require reprograming prior to
the replacement ?

∗∗∗∗ Thank you for your valuable help, especially OldCrow and his
precious website.∗∗∗∗