[sdiy] Korg Polysix Sub Oscillator Problem

[klosmon]

99 times out of 100, problems on a battery-damaged P6 are caused by damaged 
traces -- particularly the data and address lines.  Visual inspection of 
the board does not help -- many of the traces are hidden.

In this case, the front panel suboctave controls connected to the CPU board 
are D01 and P10 & P11.  Check those signals with a scope at CN06 to make 
sure they're present.  The suboscillator latch is IC34 on the CPU 
board;  check that data lines D04 - D07 are present, and that P24 is present.

~G

At 10:42 AM 4/23/2006, you wrote:
>Hi Folks
>
>I have gone back to my Polysix restoration project
>after a short break.
>
>It may interest people to know that I received this
>Polysix in pieces - Someone had literally stripped the
>Synth completely apart and taken everything to pieces
>- The only thing that wasn't separated was the ICs in
>the sockets, although some were missing.
>The CPU board had the usual battery leak damage, and I
>would assume that this is the reason why the synth was
>given to me (probably not working) and in this state.
>
>Anyway, after much repairs the synth is now
>essentially together and working, apart from two
>things.
>I had to get two replacement SSM2044 filter chips, so
>the filter settings on the sound board need setting
>correctly - Also the Suboscillators don't work, which
>is what I am now looking at.
>
>The circuitry for the subtone generation looks simple
>- Each oscillator looks to have a 4027 Dual Flip Flop
>which is used to generate the sub tone, and each is
>controlled by two lines going to the control switch on
>the panel.
>
>The sub oscillator switch right now does nothing - At
>no point do any of the six voices generate the sub
>tone. I am thinking this could be a simple loose
>connector, or maybe the Sub Osc switch is faulty, but
>I thought I'd throw this open in case anyone else has
>come across a Polysix with no sub oscillator.
>
> From initial view, the synth does not appear to have
>any loose or broken contacts. The switch looks fine
>too, although I have yet to meter it.
>
>Thanks
>Chris
>
>
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