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Subject: Re: [Roland_Jupiters] Re: JP8 question... ?

From: Mike Borish <mborish_2000@...>
Date: 2009-02-17


I had some strange problems with my Jupiter 8 too.  They were somewhat similar to yours.  Basically, I had  a high noise floor because of switching noise and the dac cycling through all of the controls on the INTERFACE BOARD. 

My solution was to replace the 47uf caps (a terrible value) with 220uf or 470uf on the rails of critical digital positions, especially the 5v rail, to prevent leakage into the analog sections.  From what I remember, the digital stuff even shares the 15v and -15v with the analog stuff.  I don't remember the names of the boards exactly, but check the MOD CON, CPU, DAC, INTERFACE BOARD, etc.  My noise floor went down significantly, my leds light up brighter, and the buttons work better.  Some of the caps were leaky too.  ALL of the caps in the Jupiter 8's are beyond their expected life now and should be replaced.


--- On Mon, 2/16/09, Gil Sicuro <gsicuro@...> wrote:
From: Gil Sicuro <gsicuro@...>
Subject: Re: [Roland_Jupiters] Re: JP8 question... ?
Date: Monday, February 16, 2009, 1:44 PM


Did you try this link?

http://www.synthdiy .com/show/ ?id=2338

http://www.synthdiy .com/files/ 2008/RolandJupit er8-ServiceNotes .pdf

Yes, there is a temporary edit buffer, since all sliders which have to do with the patch parameters are actual data entry sliders, not real analog voltage controls. If you are going to mess with vintage digital electronics (ie the manual memory buffer) I'd advise to go to a qualified tech person.


From: Quazimodo <noddyspuncture@>
To: Roland_Jupiters@ yahoogroups. com
Sent: Monday, February 16, 2009 4:18:26 PM
Subject: [Roland_Jupiters] Re: JP8 question... ?

Hi again Gil,

Many thanks for your quick reply..;~)

Yes, it is kind of strange - but I can live (and have been living)
with it. Yes, the JP8 does have the very early Kenton Midi kit installed.

The only slider that seems to have any wear (side to side play) is the
Arpeggiator speed. But it still work absolutely fine. All other
controls do what they are supposed to - like I said earlier, when you
are playing with the sliders, anything that might link to the
'popping' is quite apparent ('cos I am almost always lookimng for it!)
and I investigate anything I might see as a 'lead'... but this is
fault totally intermittent and random.

I do have a JP8 service manual on pdf but it's a crapy copy and quite
hard to read, maybe I could do with a better one..?

So there is a manual patch buffer... that would make sense. Wonder
where that lives, on which panel in the machine?

Maybe I should enqire with a tech?
I found a JP8 discussion group recently... thinking of joining there
as well.

If anyone has any ideas please let me know.

Thanks again.

--- In Roland_Jupiters@ yahoogroups. com, Gil Sicuro <gsicuro@... > wrote:
> Whoah, this is odd... does your Jupiter have any MIDI retrofit
installed? Are you positive that all sliders are ok? Grounding and
electrical conditions ok? Weird, sounds like if there were something
wrong with the temporary patch edit buffer (that is, manual). Do you
have the service manual for the JP-8?
> cheerz

> Hi Gil, and anyone else reading... thanks for the quick reply.
> Well, my JP8 has a slight fault that I would really like to get to the
> bottom of. It's nothing major but it's niggling at me to address.
> When I am in 'Manual' edit - there is a small intermittent 'pop' or
> 'click' on the audio that doesn't seem to be in synch with anything
> (like LFO speed etc...) It seems totally random.
> (At one point I thought it might have been something to do with the
> filter, don't know exactly why I thought that but you know how it is -
> when playing around with the controls you get an impression, it was
> just a hunch...)
> Anyway, if I construct a sound while in edit mode (and putting up with
> the 'pop')- and then save the patch... the resulting 'save' is 'pop'
> free...! In fact, any preset patch is fine - it's just in 'Manual'
> mode I get this symptom.
> Anybody have any ideas or come across this before please?
> Many thanks in advance....
> Cheers,
> Tom