All about the Roland Jupiter-series

~ There is a problem with my Jupiter 8:
~ on POLY 1 Mode (only) is  always one key without sound, and not enough
~ with that, this "silent" key moves around!
~ 
~ What could it be?

Must be a broken module board (which holds a set of (that's 2) combinated
VCO-VCF-VCA modules) if only one voice is dead. Try to sort out which one!
The broken voice runs through different keys indeed, and it looks as if its
totally unpredictable where it is going to be placed next. Well...that's the
processor trying to fry your brain. Don't get mad at the machine. There is a
test mode that shows the module board activity per voice by lighten-up one
of the LEDs at the voice-location section. I think I've been describing this
somtetime earlier, if memory serves me well. Please have a look at the
archives while I try to find the procedure in the technical manual.

Do you have a technical/service manual? You ARE gonna need it to fix this
kiddy...

Lemme know if I can help.

Cheers,
RVe