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Subject: Re: [korgpolyex] Joystick problems

From: Michael Hawkins <korgpolyex800@...>
Date: 2015-07-11

You need to sort out the joystick behavior first before trying to tune the master.

The tone generator is set up as two blocks of four voices each. And since you say that the first four notes hit have low tones, I would say that there is a problem with the DCO1 harmonics selection section. There's a bunch of opamps. Check the output pins of the MSM5232 while sounding notes. Then work your way through each of the opamps. Switch the waveform selection from square to sawtooth and see if one is OK and one is not. That will help to narrow down the problem.

/Mike

From: "kogz23@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Friday, July 10, 2015 2:17 PM
Subject: Re: [korgpolyex] Joystick problems

 
Now I am just trying to get the thing in tune, will troubleshoot the joystick later.
Following the service manual master oscillator procedure I can not get as high as -1oct C. The highest I can get is -1oct B. As well as this there is a problem with a massive drop of pitch (several octaves so it sounds like a crackle) for the first 4 keys hit. The next 4 sound fine, then the pattern starts again. It is not specific to any key, just the order in which they are hit. Hitting the same key twice doesn't effect the counting. I hope this makes sense!
I'm getting the correct +/-5V. Any ideas where to look? I wanna get this baby back to full life!
Thanks
Al