Discussion about the Korg PolySix synthesizer

Yeah sorry I realize pctech333 is dealing with an old 367a as well.

Well this Polysix I´m trying to restore had the battery leakage problem, which I repaired following Old Crow´s instructions. I  rewired the traces, installed a new nimh battery and new ICs 30 and 31. The programmer now seems to work, but when I try to reset the dac only leds 4 and 8 light up. 

This synth had also the other problem from the beginning: none of the pots work, just the switches. For instance, I can select any effects mode, but the speed/intensity doesn´t make any changes. Likewise, vco octave works but pwm doesn´t, and so on. 
The exception is MG not working in any way, with the led constantly lit.

I already changed the 4560 chip, which I think is the dac buffer, for a tl072. And ic20 and 21 with LM13700. I don´t have a scope yet, so that´s probably the last ic swap for now. Well, maybe IC6...

There must be some component that´s "traditionally" known for this malfunction. I don´t think it´s the memory nor the CPU. Maybe it´s the DAC? 

Cheers,

Paulo




--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
>
> Hi,
> 
> Sorry, I must be missing a post here, this isn¹t making any sense. Can you
> describe the exactly problem with the 367? I may well be able to help you
> with this...
> 
> Cheers,
> Andy
> 
> 
> On 03/11/2010 15:37, "Paulo" <inocencio66@...> wrote:
> 
> >  
> >  
> >  
> >    
> > 
> > Hi, 
> > 
> > I´ve got the exact same problem with an old 367a.
> > 
> > Can someone help, please?
> > 
> >  
> >    
> > 
> > 
> 
> 
> 
> [Non-text portions of this message have been removed]
>