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So i got this dead KORG POLYSIX from a friends friend. It sat in the box for the last 20 years, and just recently he brought it out and plugged it in. Just strange tones, nothing else. He decided to sell it broken for little more than the proce of the SSM ICs. Now i am trying to restore this beauty. Below you will find my blog for this journey.

I owe special thanks to Ko Okatake from Modeless Factory/Japan, who more than once kindly pointed me in the right direction, and Scott Rider aka Old Crow, who uploaded a nice tutorial about the crucial battery replacement.

Now lets see...

Humming again.

Posted by fonitronik

It has been quite a while since the POLYSIX is working again, i just forgot to share the video of proof here. There is still some work to be done, though. I will have to realign the front panel components PCBs (center the postentiometers again), and i will replace the momentaries. The replacements are already waiting in the drawer.


Posted by fonitronik

The new opto arrived yesterday. Since everything was prepared already (socket installed) i just had to put the new opto in it`s socket - and now the POLYSIX is purring like a cat again!

While playing with the synth i recognized two weak program switches. Now i will have to find those replacement switches i bought a while ago...


Posted by fonitronik

While i am waiting for some replacement parts i started to replace the old electrolytic caps of the PSU.


Advanced Optics

Posted by fonitronik

Now the KLM-366 is on the bench.

Stefan Hübner has some good info on the opto coupler in the Polysix' Antilog circuit. And thanks to his article i am able to almost be sure that the scale issue is caused by an error in the Antilog circuitry. I measured -13V at pin 7 of IC 18, indicating that something is not working as expected here.