Hi there,
First thing I would do is check the Reset circuit according to the
service manual. The reset pulse can be adjusted. The service manual
along with the adjustment procedure is available at the web site of
"Old Crow":
http://www.oldcrows.net/~oldcrow/synth/korg/polysix/manuals/service/miniserv.htmlThe reset input to IC22 is pin4. It must be high (ca. +5V). If it is
below 3V the reset circuitry (around IC5) is faulty.
The next thing you can check is whether the 8048 is running:
monitor test point "CLOCK" left of the 8048 with an oscilloscope.
There must be a short pulse every 20msec.
The third thing is to check whether the crystal oscillator is running.
monitor pin 3 of IC22 (8048). This is the crystal osc. output. There
must be an oscillating waveform with about 6MHz. If you do not have
an oscilloscope you can monitor this pin with a DVM; it should read
about the half supply voltage which will be 2.5V in this case. If the
crystal is not running you can unsolder the resonator X1 and obtain
the 6MHz from KLM-366: route a wire from KLM-366/IC4/pin3 (Key Assigner
CPU) to KLM-367/IC22/pin2.
If you feel very confident that your 8048 chip is blown you may contact
me, I have a lot of them on stock. I think "Old Crow" has some of them,
too. But my eperience is that very seldom the CPU chip is defect. Much
more likely some of the circuitry around is the cause.
If you are really desperate about your Polysix you may contact me.
You can send me your KLM-367 board and I repair it for you. We have
to agree about the conditions.
I hope this helps,
Johannes
Have a look at (you will find my private email address there):
http://analog.no/polysix/index.htmPolySix@yahoogroups.com wrote:
> What happens when I power on my Polysix is this: All led's lit up
> steady except för the freq. led on the MW section. It starts
> blinking
> slowly and speeds up until it's a steady light. Another exception is
> the speed led on the arpeggiator section it blinks correct according
> to the speed set on the nob. I guess the the synth i s stuck in the
> reset mode witch should last a couple of seconds but I've waited for
> houers. Of cource there is no sound what so ever. If I remember
> correctly it started with a waiting time of a couple of minutes and
> gradualy got worse over time. I have tryed the repare of a leaking
> battery, and whas optemistic since there where at leased one trace
> damaged. After first repair it still would'nt work so i ended up
> replacing all traces around IC31 .... but no luck!
>
> So I'm hoping that anyone out there has a clue how to fix it. Maybe
> there is some components at the reset circutes that has to changed.
>
> Thanks
>
> Christer
>
>
>
>
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