All about the Roland Jupiter-series

-----Original Message-----
From: Cary Roberts [mailto:Cary.Roberts@...] 
Sent: Friday, September 10, 1999 1:21 AM
To: mark scetta
Cc: Analogue Heaven
Subject: Re: [AH] kenton jp8 midi kit


>after many hours of a careful installation, i am having serious difficulty 
>getting the midi kit on my jp8 to work. the unit has no midi activity 
>except sending an occasional (random) program change when i hit a key.
>
>kenton is not cooperating, which i am extremely disappointed with. i will 
>never deal with them again. is there someone with a good knowlege of this 
>kit that can help me troubleshoot it? does anyone have the actual 
>schematics of the analog & digital boards that make up the brains of the
kit?

First thing to do, pull out all connections from the Kenton analog 
board to the synth.  Restore unit to normal operating capacity.  This
may be as simple as pulling out the harness connector on the analog
board, but on other synths like the memmoog and P5 it is not.

Disconnect the ribbon cables from the keyboard to the Kenton digital
board and re-establish that the JP-8 can still work on it's own.
Once you've done that, hook up the keyboard cables to the digital
board and see if it still works.  If not, recheck DIP connector
orientation.  If you get that to work, good, see if you can get
the JP-8 to play via MIDI.  Only after getting the unit to play
on it's own and via MIDI should you reconnect the Kenton analog
board connections to the synth.  Before doing so, put a voltmeter
on the VCA and VCF CV outs, and make sure you can they change
value with the appropriate MIDI CC command.  If not, there is
a problem.  Probably a bad 4051 demux.  An oscilloscope comes
in real handy for diagnosing the problem at this point.  If you
can see the CVs on the analog board, then reconnect them one at
a time to the JP8, and check out each for proper operation before
proceeding to the next.  It is possible for the VCF or VCA CV
to make the JP-8's output inaudible, making it appear the unit
is not functioning.

If none of the above fixes the problem, return it, sell it on
ebay, or throw it away.  Then buy an Ecore Electronics kit which
is a superior product, interfaces directly to the original processor,
and adds much more versatility.

-Cary