All about the Roland Jupiter-series

~ 1)the bender box: VCF and VCO mod(the white button for mod
~ lfo) does not
~ work when the VCO and VCF is assigned.???yes I have turned up
~ the faders all
~ the way as well! what could be wrong???

Does the 'portamento' and 'bend' functions work? This could be many things,
but most likely it will be a loose contact... There's only one way to find
out...open the box and check all possible connections. If the whole panel
doesn't work, this might be easier to fix than just one or two
non-functioning buttons/sliders.

~ 2)the other problem is while playing in WHOLE MODE: the 2nd
~ OSC of the 4th
~ voice has no sound(poly-2 i think). When i first got the
~ machine, I played
~ down the keyboard starting at the top and every 8th note did
~ not work, now
~ instead I can play the same note over and over again and its
~ always the 4th
~ voice OSC 2 that does not work.does this sound like a a OSC
~ chip.....but it
~ does not happen all the time???

The voicing-cycle in the JP8 (at least on mine) doesn't make any sense
whatsoever. I have not been able to find a pattern in the way the processor
devides the voices. This results in (when having a faulty osc) 'random'
drop-outs.

I've seen this problem before and it cannot be anything else than a faulty
osc. Again you need to open the box in order to find out which one doesn't
work. So, dig up your screwdrivers, soldering iron and scope. Tip: You may
find the circuit diagram of great help...

The JP8 holds four boards with two oscs each. Once you've found out which
osc is faulty, next thing is to find out which element doesn't put through
the signal and determine if this requires either a custom or a 'regular'
part. You might be in trouble if it's a custom part... Roland doesn't have
loads of ICs on stock from the older machines...but you could try it with
them.

~ 3)when holding down the numbered buttons to the right of the
~ display 1 and 3
~ while powering on the jupiter-8, the display shows the
~ version of keyboard
~ scanning, after that every time I play a note the buttons
~ light up(led's) is
~ this meant to happen on normal power up operation?(without
~ holding down
~ buttons 1 and 3?

No, when holding down the buttons during power-up, you put the machine in
test-mode. The lit LEDs show the osc that is sounding. 'Reboot' without
pressing any buttons should put your machine back in 'normal' mode.

Cheers,
RVe

~ the only thing that does not work is that LFO
~ white button,
~ and the knob for the lfo rise time, the portamento works
~ fine, what i think

The LFO-button (the white one) has the reputation of being a bit sloppy with
reacting to the presuure you put on the cap... In other words, these things
break easely. I'm currently installing my fourth (!) LFO button... You might
want to replace the button and the electronics underneath with a new block
(if you can get one).

~ i just realized is that the jp only skips this note on the
~ 4th voice only in
~ the test mode. when powering up in normal mode as ya said, i
~ think it works
~ fine. thanks.

You really should test this to be on the safe side. You don't want the JP to
drop out on you on a gig...? Do you?

Cheers,
RVe