Customer brought in this Roland Juno 60 asking for a total restoration. The Roland turned on but only played some crappy noises. First thing I noticed, there were no sounds in memory, so the battery seemed to be empty and was replaced.
Loading the factory patches brought the synth back to live. At least with 4 voices. Then I noticed, that I could not edit any sound. The problem was solved by replacing a dead comperator IC (pcb top, the socketed one).
Besides that the fader dust cover were worn out and needed a replacement, I figuered out that the two dead voices had a problem in two dead IR3R01 envelope generator ICs. Well, the problem is to find one. A working one. At a decent price. These parts are obsolete and I had to figure out a replacement.
Lucky me there is a nice person who did an envelope chip that could be used. I mean an ENVGEN 8C VCADSR Envelope Generator created by electric druid. https://electricdruid.net/product/envgen8/
It´s not a drop in replacement, so I had to add some components to it.
After I came up with a solution I noticed, that it was again not a direct replacement. The two new voiced had a slighty different timing in the ADSR, so that in some cases I could audit a difference between the two new voices and the four working IR3R01 .
I spoke to my customer and we decided to swap all IR3R01 to the new solution. Which then worked great. No difference between each voice, which is great. The juno just sounds amazing again. So it was worth to also clean/refurbish all faders, switches, buttons, jacks and of course the keyboard and contacts.
There are lethal voltage exposed in electronic devices. Unless you know what you are doing, don’t try this. If you following along, you doing so at your own risk.
I’m documenting repairs for my reference and yours.
I do synth restorations and repair with a specialty in vintage synthesizers, drum machines and other vintage gear, based in Düsseldorf, GER. Get in touch about your synth situation!