Possible Repair Technique for the 80017a, the Juno-106 Voice Chip

YouTube via rolandsh1000

"Upfront, I'd like to say that I take no credit for inventing this technique, only for demonstrating it. I was inspired to try it by two compelling images that a person named Ramcur had posted on Flickr. I emailed him and he told me what he had done. So very special thanks to Ramcur for the method, and thanks to Chris Strellis (http://www.strellis.com) and K/Modeless Factory (http://modelessfactory.com) on the Analog Heaven mailing list for sending me sample failed chips to test this method out. Please visit their sites and patronize their services!

Some background: my HS-60 had 4 bad voices so I removed those 80017a's with plans to buy clones sometime in the future. But after I stumbled across Ramcur's photos, I tried to see if these chips could be repaired. I first used a professional heat gun, and I was able to salvage 2 of the 4 chips satisfactorially by simply removing the resin coating of the chips (the right heat allowed me to peel the coating off). But that was still only 50% yield and about 30minutes messing around with the heat gun - not easy.

After Ramcur emailed me back about using acetone, I tried it on a bad 80017 that Chris Strellis had sent me and it worked great. So I decided to create a video to show how this might be done. In the video, my HS-60 has been fitted with SIP socket to allow for quick swap out of the chips for testing. These sockets are in voice slots 2 and 3. Slot 1 has a 'known good' chip for comparison. In the final part of the video, I installed the chip that I was able to get "cleaned" in slot 2 for comparison to the good chip in slot 1 (slots 3, 4, 5, and 6 have no chips/are empty). I apologize for the bad lighting in that last part.

Does this really fix the chips? What about longer-term performance? The chips I've "rescued" so far I have put in my constantly-powered-on HS-60 for over a week and checked them twice a day and all of them no longer had any popping or cracking or cut-outs or runaway resonance or any of the classic failure modes of the 80017a. They did sound slightly different chip-to-chip, but I think that was due to me not recalibrating the trimmers for each voice.

Should you try this? I'd say you have nothing to lose and, as I show, it's pretty easy to do. If you already have a bad voice chip in your 106 or HS-60, you already would have to desolder it to install the reportedly-excellent clones from D'Naab (http://www.analoguerenaissance.com). So you could try this method first and, if it doesn't work or it's not to your liking, or you just want the comfort of something pretty much guaranteed, then you can always get the clone.

As the weeks go forward and I get time, I'll be subjecting this method to a lot of known-dead chips. I'll try to report back how that goes.

Good luck!"
Roland Juno-106 chip fix - IC repair