Discussion about the Korg PolySix synthesizer

Doh - yes, sorry, I can't count ;)  8 dead keys. 
Thanks for the schematic (curiously, there didn't seem to be one in Korg's original service manual!) 
I will try to check the continuity of the D0 line in the multiway cable ... if it's broken then maybe I can fairly easily solder a replacement in. (Sadly the cabled seems glued to its socket, so I can't just swap it!) 


--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@...> wrote:
>
> Hi,
> 
> I discovered that the attachment did not go through with the email. So
> I uploaded the wiring diagram to the files section of the list.
> http://launch.groups.yahoo.com/group/PolySix/files/PS6_KEY.PDF
> 
> Johannes
> 
> 
> On 30.07.12 20:56, Johannes Hausensteiner wrote:
> > Hi,
> >
> > The Polysix scans 8x8. So 9 keys failing would be rather odd.
> > But from G1 downwards it's only 8 keys... So we're back in the game.
> > The low eight keys are read through D0 (see attachment).
> > Check for continuity from the Kyboard PCB to MIDI Module/IC5/pin4.
> >
> > Good luck,
> >
> > Johannes
> >
> >
> > On 29.07.12 00:27, Peter Mörck wrote:
> >> Hi,
> >>
> >> Speculations ahead. Skip to next part if not interested :)
> >> There are 16 wires going to the keyboard.
> >> I can't from the schematics tell if the keyboard is scanned as 8x8 or 7x9.
> >> 8x8 would probably be more "natural" as it allows the P-pins to set "row" and the DB-pins to read column, so to speak.
> >> It requires 8 partial scans, scanning 8 keys at a time. Maximum number of keys 64.
> >> On the other hand, 7x9 might be faster since it only requires 7 scans, scanning 9 keys at a time while still allowing a maximum of 63 keys.
> >> Since we only have 61 keys, and you say 9 keys are dead, I would guess it scans as 7x9.
> >>
> >> Next part:
> >> I suspect one wire to the keyboard is open circuit somewhere, or perhaps one of the diodes on the keyboard board?
> >> I don't remember how the diodes are connected on the keyboard and I'm too tired to figure it out :)
> >> Do continuity testing from the solder side of the keyboard connector to where the cable is soldered onto the keyboard board.
> >> But first, wiggle the keyboard connector a bit and then press it down firmly and see if that helps.
> >> It's probably attached with some glue but .. well.. heh..
> >> There are no components between the keyboard and the keyboard scanner controller, though there are other things on those lines as well that might interfere if fried, though I still suspect it's just a mechanical problem with the connector or some solder joint.
> >>
> >> BR,
> >> Peter
> >>
> >>
> >>
> >>     ----- Original Message -----
> >>     From: feline1973
> >>     To: PolySix@yahoogroups.com
> >>     Sent: Saturday, July 28, 2012 11:33 PM
> >>     Subject: [PolySix] dead keys :(
> >>
> >>
> >>
> >>     My Polysix has developed a fault with its bottom 9 keys (G downwards) -
> >>     first they started intermittantly failing to trigger when pressed,
> >>     then they started doing odd things like being silent when held down together...... and now they're all just dead.
> >>
> >>     I dismanted the keyboard assembly and cleaned the conductive studs and contacts on the circuit board - didn't help. I doubt very much they're the problem, as swapping different rubber stud-holders around doesn't change things.
> >>     I'm wondering if the multiway cable between the keyboard and voice board could be the culprit? Maybe just one of those yellow wires is dud?
> >>     I can't even get it out to swap it, the keyboard end is stuck in its socket.
> >>
> >>     Any suggestions?
> >>
> >>     (Oh, and it all plays perfectly if trigger exterenally via MIDI - I have Johannes Hausensteiner's retrofit)
> >>
> >>     David
> >>
> >>
> >>
> >>
> >>
> >> [Non-text portions of this message have been removed]
> >>
> >>
> >>
> >> ------------------------------------
> >>
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> >>
> >>
> >>
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> > ------------------------------------
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