I’ve got a Juno 106 apart that’s driving me nuts. I have dead keys and I cannot find the culprit. I’ve checked traces, solder joints, and replaced diodes on the key matrix and the unobtainable Motorola 4069 cmos chip too. They don’t correspond to a common address line in the matrix, it’s not dirty contacts, and it’s not broken pcb traces. Does anyone have a Roland tech in the southeast?
Did you check the rubber contacts under the keybed, I had once a Roland keyboard in the past I had to change several rubber contacts I was lucky to source directly from Roland, you could just try to clean up the rubber and PCB contacts with alcohol to see if that helps, otherwise try hear with Roland if they still have spareparts for your 106.
How did you check the solder joints, if only by visual inspection it's easy to miss eventual micro cracked joints, if so one can only try and run a solder pen over all the joints to be sure to rectify that potential culprit.
btw 4069 and many other 4000 series CMOS chips are still available, TI is one supplier, Motorola became ONsemi though but didn't check what their status is nowadays.
Here's a pretty nice Juno 106 restoration article that might help you.
http://blog.batzi.com.au/2019/11/restoring-a-roland-juno-106-in-pictures/
and another one..
https://gearspace.com/board/geekzone/1012954-roland-juno-106-full-restoration-walk-through.html
Just my 2c, good luck.
How did you check the solder joints, if only by visual inspection it's easy to miss eventual micro cracked joints, if so one can only try and run a solder pen over all the joints to be sure to rectify that potential culprit.
btw 4069 and many other 4000 series CMOS chips are still available, TI is one supplier, Motorola became ONsemi though but didn't check what their status is nowadays.
Here's a pretty nice Juno 106 restoration article that might help you.
http://blog.batzi.com.au/2019/11/restoring-a-roland-juno-106-in-pictures/
and another one..
https://gearspace.com/board/geekzone/1012954-roland-juno-106-full-restoration-walk-through.html
Just my 2c, good luck.
I did clean the key contacts, and I have verified they aren’t the problem by jumping them to good notes. This would suggest an address line issue but all dead keys are on different lines. I have touched all of the solder joints on the key bed at this point and verified they’re good