[sdiy] Korg Polysix major problems - Update

[Karl Ekdahl]

Guys

One last question before i give up on this CPU; how common is the problem of the CPU dying and *which* CPU are we talking about, the 8048 or the 8049 (i believe the latter might be my problem). The reason i'm asking is because i in fact have two sets of boards for the polysix and each board behaves the same which i thought was kinda weird. I have of course tried swapping the CPUs inbetween the boards as well as hooking up all of the boards with eachother in different configurations.

Karl


--- Den fre 2008-10-24 skrev Ullrich Peter <Peter.Ullrich at kapsch.net>:

> Från: Ullrich Peter <Peter.Ullrich at kapsch.net>
> Ämne: Re: [sdiy] Korg Polysix major problems - Update
> Till: "elektrodwarf at yahoo.se" <elektrodwarf at yahoo.se>, "Bob Weigel" <sounddoctorin at imt.net>, "synth-diy at dropmix.xs4all.nl" <synth-diy at dropmix.xs4all.nl>
> Datum: fredag 24 oktober 2008 08.26
> Hallo Karl!
> 
> It seems that you could use a new programmed 8748 or 8749
> microcontroller.
> As you are from Sweden as your emailaddress tells me you
> may be interested
> in getting a new microcontroller from me.
> 
> I need to have a look but I am quite sure that I still have
> some left.
> It would cost 10 Euro + postage.
> 
> Mail me privately if your interested and I will have a look
> if I can find
> A chip.
> 
> Tip: If your existing microcontroller is socketed (normally
> they are) try
> To remove it and put it in again - maybe the malfunction it
> is just because
> of corrosion.
> 
> Ciao
> Peter
> 
> http://www.ullrich.at.tt
> 
> 
> -----Ursprüngliche Nachricht-----
> Von: synth-diy-bounces at dropmix.xs4all.nl
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] Im Auftrag von
> Karl Ekdahl
> Gesendet: Freitag, 24. Oktober 2008 04:27
> An: Bob Weigel; synth-diy at dropmix.xs4all.nl
> Betreff: Re: [sdiy] Korg Polysix major problems - Update
> 
> 
> Bob
> 
> > Well normally there will be a dead or multiple dead
> lines that should
> > be chugging away with the clock generating data and
> addresses.
> 
> Oh no, i just verified that out of the eight lines going
> out of the processor (pin 34-27) only two are actually
> having any data on them, the others are totally stale.
> 
> > And then you
> > have to establish if it's the cpu or something
> pulling a line down.
> 
> Hmm.. i didn't even realize these lines both go to the
> keyboard as well as to the KLM-371 - perhaps if i disconnect
> the cable to that board i'll at least see on which board
> the problem is.
> 
> > The code is inside of course so unless it's
> rapidly halting for some
> > reason there should be stuff going on with all those
> lines.
> >  I can't
> > recall off the top how reset etc. are set up on that
> chip so consult
> > diagram and besure those lines are doing what they
> should do also.
> > Usually held low a reset is active to keep the chip
> out of the game.
> > -Bob
> 
> Now i'm a little confused; are we talking hardware
> (memory) reset or a soft reset while power is on? I know
> there's a reset POT on the KLM-371 board but i don't
> really know what it's doing, guess i've gotta dig
> into the 8048/8049 datasheets...
> 
> As it does seem like i might need a new processor, did you
> say you had some? Would you be ok parting with one in that
> case and for how much?
> 
> Thanks
> 
> Karl
> 
> > Karl Ekdahl wrote:
> >
> > >So, it turns out that there is a good clock going
> to
> > IC4 / IC5 that handles the gates, it's just not
> doing anything - the
> > data coming in seems fine and the reset is constantly
> held HIGH as far
> > as i can tell. I desoldered IC4 and tried triggering
> the gate on voice
> > 4 manually and indeed it works just fine! The thing is
> though that it
> > doesn't change frequency when i push any of the
> keys and the D/A i've
> > verified to work so perhaps there's something else
> busted in the
> > keyboard section?
> > >
> > >
> > >
> > >>I've had a cpu go bad on that board.
> > That'd be
> > >>first guess. You can of
> > >>
> > >>
> > >
> > >How do i verify if the CPU is dead?
> > >
> > >Thanks
> > >
> > >Karl
> > >
> > >
> > >
> >
> __________________________________________________________
> > >Låna pengar utan säkerhet. Jämför vilkor
> online hos
> > Kelkoo.
> >
> >http://www.kelkoo.se/c-100390123-lan-utan-sakerhet.html?partnerId=969
> > >15014
> > >
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> >
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> > >
> > >
> > >
> > >
> 
> 
>      
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