[sdiy] Korg Polysix major problems - Update

[Ullrich Peter]

Hallo Bob and Karl!

Maybe the testing and calibration description in the Polysix service manual can help you.
You can find the complete service manual (not only the schematics like on most Polysic sites) on Florian Anwanders site:
http://fa.utfs.org/diy/korgpolysix/polysix_service_manual.pdf

Regarding which CPU could be dead: Due to your description I would say the key assigner chip 8049 on the
board KLM-366 is dead or not working due to other reasons.

Ciao
Peter

http://www.ullrich.at.tt


________________________________________
Von: synth-diy-bounces at dropmix.xs4all.nl [synth-diy-bounces at dropmix.xs4all.nl] im Auftrag von Bob Weigel [sounddoctorin at imt.net]
Gesendet: Freitag, 24. Oktober 2008 20:55
An: elektrodwarf at yahoo.se
Cc: synth-diy at dropmix.xs4all.nl
Betreff: Re: [sdiy] Korg Polysix major problems - Update

Hmm...yeah that doesnt' sound real likely.  Like I say I had an 8049 go
down recently while troubleshooting the other board which was bizarre.
Swapped in the chip from a spare board and voila.  But I'd have to
review diagram for that section to think of some good procedures and I'm
a bit busy for a few days here.  Maybe somebody else has a thought off
the top on that.  Trying to recall how the reset line is on that cpu
etc. -Bob

Karl Ekdahl wrote:

>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
>>
>>
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>>>
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>>>
>>>
>>>>15014
>>>>
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>>>>
>>>>
>>>>
>>>>
>>
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