Discussion about the Korg PolySix synthesizer

Andy,

Many thanks for the wise words, I´ll check the data bus asap.


--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
>
> Hi Paulo,
> 
> Yes, afraid to say this is what I used to do when I first started repairing
> Polysix. Changing just about every IC in the hope that it would fix the
> problem. After the first six or seven you start to realize that these types
> of whacky fault are almost exclusively down to o/c tracks. Get yourself a
> logic probe and check all the points where the data bus (D00-D07) terminates
> and make sure you have pulse trains on these lines. Bet you one or more of
> them do not terminate.
> 
> You asked if any components are Œtraditionally¹ associated with this type of
> problem? Yes, o/c tracks. If this board is causing you real issues and is
> severely damaged then I would recommend you seek out the parts and build
> yourself a clone. You won¹t regret it.
> 
> Cheers,
> Andy
> 
> 
> On 03/11/2010 19:13, "Paulo" <inocencio66@...> wrote:
> 
> >  
> >  
> >  
> >    
> > 
> > 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 <mailto:PolySix%40yahoogroups.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]
> >> >
> > 
> >  
> >    
> > 
> > 
> 
> 
> 
> [Non-text portions of this message have been removed]
>