The voices are enabled by the six gate signals,
which come from IC4 and 5 on the KLM366 board.
The Polysix doesn't check for bad voices or anything
that I am aware of. Check the gate signal for that voice.
If it's not turning on, then maybe change out the 4175 chip.
On the EG testing, I would monitor the voltages at IC10-1,
IC10-7 and IC11-7 in manual mode as you adjust each
front panel control. See if the voltages follow the controls
smoothly, or if they jump to match what you are seeing.
If the behavior is the same for all voices, then it seems it
must be some issue with these voltages, not an EG chip.
If the voltages jump, then I would replace the 4051 (IC18),
assuming the other controls are working OK (DAC is OK).
You may also want to buzz out the connections from IC22 and IC23
to pins 6,9,10, and 11 on IC18. If there is a problem with one of those
signals, it could cause strange behavior on the outputs of that chip.
You should grab a copy of the service manual if you don't already
have it, so that you can check the schematic.
Let us know what you find.
Bob
From: "dtonthept@yahoo.com [PolySix]" <PolySix@yahoogroups.com>
To: PolySix@yahoogroups.com
Sent: Tuesday, June 3, 2014 11:33 PM
Subject: [PolySix] Dead voice and too fast EG
Hi folks,
I'm wondering if anyone might be able to chip in with regards to the below coupla problems I'm still having on the Polysix I picked up recently (and just successfully switched to the Kiwisix including psu mods). The below's behaviour has been consistent before and after installation of the Kiwisix.
Firstly, voice two isn't sounding. The LED is not lighting, and that's about all I can tell you at this stage. From the threads I've trawled there seems to be a pretty systematic way to troubleshoot this but I haven't been able to locate that information, including what the significance is of the LED not lighting (I've seen threads where a voice isn't sounding but the LED does light....). Can anyone point me in the direction of a step-by-step or otherwise hold my hand for a bit?
Secondly, very strange behaviour from the EG. The AD and R make no change from a value of 0 till roughly 6 (staying as they would at 0) then there's a small change till 8.5 or 9 or so (by which time they sound as you'd imagine they might around 3 or 4) then no change for the remainder of the travel till 10. It's the same with all three of these pots. I tried adjusting VR12 but this just applies an offset to this time for each voice, and doesn't change the fundamental behaviour. I'm totally lost on this one!
Any wisdom, humour, advice, direction, or even solutions most welcome.
Thanks a million,
D :-)