Some keys don't produce sound on my Juno 106

I would guess that also there are some bad voice chips but, I’m just curious what to check for certain keys not working. Some Ds work other Ds don’t work. It’s all the way up the keyboard in every octave but inconsistent which keys… Which is different than the round robin thing with the voices so that’s why I’m asking here…if there could be something else causing some keys to not produce sound. Cheers!

The keyboard is an 8x8 matrix. Is it every 8th key?

I’m trying to get the epoxy coating off of the voice chips right now but that very well could be the case.
I know there are some voice issues so I’m starting with that. Hopefully I can reflow the components and get some improvements. Once I get these voice chips back in I’ll verify as to which keys are working. But obviously there is something going on with the matrix. The issue is uniform up the keyboard. I’m open to suggestions. Cheers!

That coating sounded like a nice idea in manufacturing: seal up a circuit into a component. But from what I’ve read, that coating is the problem with these voice cards.

Fortunately, there are cloned chips if you don’t have any luck with that. I had a bad chip in my Juno 2, and there aren’t any clones for the IR3R05.

There’s a possibility of an issue on the CPU board. The columns are tied to +5 through a resistor array, and then they go through a bank of inverters before arriving at the cpu. But these lines are also connected to the buttons on the control panel and MIDI board. Any issues with a bank/patch button?

More than likely a break on the contact board. If the whole column is out, I’d bet it’s near the connector.

I’m not having any issues with banks and presets. Everything seems to do what it needs to do so far aside from the keys issue and the voice issue. But, I wanted to try and get the voice issue squared away because I though that might have something to do with the voice card. But it likely is another issue altogether. My next task is to get that epoxy off and reflow those voice boards and pop them back in and see what happens. I’d live to toss 350 bucks worth of voice chips in but my bank account is telling me to slow my roll.

I quite agree. I spent around $40 trying to get the aftertouch working on my Juno 2 and thought that was getting crazy. I already spent $50 on the IR3R05 chip, and if another one goes it’s just going to be a MIDI controller.

Good luck with the epoxy!