All about the Roland Jupiter-series

From: mark scetta 
Subject: [AH] help: jp8


hi folks,

my jupiter 8 is exhibiting strange behavior and i could use some help. upon
power up, i play 8 keys (as in a scale) and the 8th note sticks, i.e. the
envelope doesn't close on it.  i am trying to troubleshoot the problem
further. so i have swapped voice boards (which are identical on a jp8)
around inside the unit and the problem remains the same. which leads me to
suspect the module-controller (mod-con) boards or the cpu board (or
something else?). can anyone provide some help from this limited
description? i have: a DVM, oscilloscope, jp8 service manual, not enough
knowledge on using them (but i can follow instructions well).

thanks
mark