Discussion about the Korg PolySix synthesizer

Yes it has been acid damaged and has been serviced by another tech before me and has not done a proper repair.

I have checked IC 30 and 31 and had one cable on the wrong place
(my bad :)) 

It now sounds as it should and the modulation of the sound is gone.
All the switches on the 369 is still not working and will have to do a follow up on that. It works on the 370!
The reset circuit is still behaving badly and will replace the pull-down diod D2 and see if it helps?
When I put switch in test mode it wont do any change when I change the DA trim? It did before.

So back with the scope and check some more and thanks for the input so far.

/Robert



--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
>
> Hi Robert,
> 
> Are you repairing a board that has been acid damaged? That is an awful lot
> of silicon to be changing in one go! If you can�t set up the reset circuit
> properly and just get a permanent active low in test mode then try replacing
> zener diode D2. As far the switches being in trouble do check the operation
> of the quad latches IC28/29/34/35. Moreover make sure there is a pulse train
> at the clock pin (5). If this board has had an acid spill then the lines
> back to P24/25 on the CPU are prone to becoming disconnected as they run
> under where the battery used to be!
> 
> Cheers,
> Andy  
> 
> 
> 
> 
> On 23/02/2011 17:57, "robobob66" <robertleiner@...> wrote:
> 
> >  
> >  
> >  
> >    
> > 
> > Hello list.
> > 
> > I'm working on a broken KLM367 where i so far have put new logic
> > on IC 30, 31, 24, 26, 28, 29, 34, 35.
> > 
> > When i test the reset circuit with a 56kohm dummy all the leds light up but
> > won't change when i adjust VR1. It only changes when i remove the dummy and
> > adjust on VR1.?
> > 
> > The polysix makes sound and all pots works except all the switches on KLM 369
> > dont work. The sound it self sounds like its being modulated by an fast lfo
> > that wont go away and it's not from the polysix lfo! bad A/D?.
> > 
> > Ok, any light on this matter is help full!
> > 
> > /Robert Leiner
> > 
> >  
> 
> 
> 
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>