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.PDFJohannes
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
>>
>>
>>
>>
>>
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>>
>>
>>
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