Cracking the hood of the Roland Jupiter-6

xpander · Post by **xpander** » Tue Jul 03, 2007 3:46 am

well, i've had the Joop for nearly two weeks so i figured its time to crack it open and send off the controller board for the Europa modification.

i thought you might enjoy marveling at its insides with me- it wasn't as dirty inside as i expected!

controller board- Intel Inside!

most of the VCOs- 8 CEM3340 chips pictured. they are half the size i was expecting!

the other four 3340 VCOs, plus the ghosts of what could have been a Jupiter-8

some of the IR3109 VCFs

power supply and fuses

the underside of the PCB under the control panel

more VCF chips, VCA chips including the CEM3360

Post by **Mixolydian** » Tue Jul 03, 2007 4:23 am

Great pics - thanks. It's nice how Roland used to design their cases with the hinges.

I love opening and looking at the insides of my synths. I usually look up all the ICs to see what's what.

thisispainful · Post by **thisispainful** » Tue Jul 03, 2007 5:29 am

yep i remember looking around inside there too. it is very interesting how these old synths were made to be worked on if needed.
i have thought about doing the europa mod on my jp6 for a while now.
such a great synth.

translucencecs · Post by **translucencecs** » Tue Jul 03, 2007 5:45 am

Jaysus. There's genuinely more c**p inside of my MS-2000R...

How'd you get one that clean?!

xpander · Post by **xpander** » Tue Jul 03, 2007 6:02 am

what i'm really dreading is taking it even further apart to replace the pots... two of them need to be replaced, but i'm buying a whole set of replacement pots/knobs. that looks like a very tricky task.

i like seeing the insides of these old analog synths, too, they are extremely easy to understand with their large, discrete components and basic ICs compared to the meaningless array of advanced digital logic chips, multilayer PCBs and surface-mount components of modern digital hardware.

xpander · Post by **xpander** » Tue Jul 03, 2007 6:06 am

translucencecs wrote:Jaysus. There's genuinely more c**p inside of my MS-2000R...

How'd you get one that clean?!

i swear, when i bought this thing for $700, the guy selling it to me probably would have gone lower in price. the Korg Radias above it even cost more at $750. but do stop to appreciate the little dust bunny on the second VCO picture.

drawtippy · Post by **drawtippy** » Tue Jul 03, 2007 6:17 am

great pics!

I was so scared going into that city of wires and boards and chopping out the motherboard but the Europa people and their mod is absolutely genius. Too bad about no LFO sync but otherwise it turns the 6 into an analog beast with modern features. Don't forget to try the random patch generator!

xpander · Post by **xpander** » Tue Jul 03, 2007 9:11 am

extracted the controller board...

disconnect & unscrew

an unforseen hitch! the wires are tethered to the PCB

damn, its nice to have the right tool when you need it

removed

the extracted board!

StepLogik · Post by **StepLogik** » Tue Jul 03, 2007 1:36 pm

you did remember to mark which connectors go where, right?

if not, you can trace it down using the service manual.

xpander · Post by **xpander** » Tue Jul 03, 2007 7:37 pm

StepLogik wrote:you did remember to mark which connectors go where, right?

if not, you can trace it down using the service manual.

i sure did... plus i took lots of pictures!

Alex E · Post by **Alex E** » Tue Jul 03, 2007 8:29 pm

Very nice! It's interesting that they would have those empty spaces for more components that would be on a Jupiter 8. Does that make it technically possible to modify a Jupiter 6 to be a Jupiter 8?

btw, Ensoniq also did that nice hinged case style, and it was also that way on my DX7. It's too bad synth manufacturers don't do that much anymore. It makes working on synths a lot nicer.

xpander · Post by **xpander** » Tue Jul 03, 2007 8:57 pm

Alex E wrote:Very nice! It's interesting that they would have those empty spaces for more components that would be on a Jupiter 8. Does that make it technically possible to modify a Jupiter 6 to be a Jupiter 8?

btw, Ensoniq also did that nice hinged case style, and it was also that way on my DX7. It's too bad synth manufacturers don't do that much anymore. It makes working on synths a lot nicer.

i've heard that brought up before, but it would be safe to say if it were possible, it would be the most popular mod for the Jp6.

it seems like using the same pcb layout on different versions of the same line of products is still pretty common, especially in computers where making two pcb layouts would be formidably expensive. in some cases, they are exactly the same except they have a jumper that limits performance. weird, eh?

StepLogik · Post by **StepLogik** » Wed Jul 04, 2007 4:28 am

the architecture of the jp-6 and -8 are different. - even if you brought a jp-6 up to 8 voices its still quite a different instrument.

the two jp-6 voice boards are the same, just half the voices are populated on the 2nd one. this saves manufacturing costs since they don't have to print 2 board designs (one 4 voice, one 2 voice).

if you look at the jp-6 service manual, it doesn't look like you could drop another 4-voice board in place of the 2-voice and get an 8-voice jp-6. it looks like the firmware and the addressing depend on a 2 and 4 voice board. each board has its own slave CPU which receives data from the main cpu and directs the S&H for supplying CV voltages to the voice circuits.

we discuss this a bit in my restoration thread, but i think it would have been cool if roland had written the firmware for the main cpu to be robust enough for it to interrogate each voice board to determine if it was a 2 or 4 voice. depending on which combination of boards you have, the main cpu adjusts the voice allocation algorithm accordingly.

neandrewthal · Post by **neandrewthal** » Wed Jul 04, 2007 6:13 am

Couldn't that be rewritten by sombody very smart? Like the people who make the europa upgrade? Personally I don't see the need for 2 more voices though. I can't say that I ever play 4 note chords with each hand at the same time, or need more than 12 oscillators stacked in unison mode.

Xab · Post by **Xab** » Wed Jul 04, 2007 6:45 am

StepLogik wrote: the two jp-6 voice boards are the same, just half the voices are populated on the 2nd one. this saves manufacturing costs since they don't have to print 2 board designs (one 4 voice, one 2 voice).

Hi,

if I remember correctly, not only what you stated is relevant, but also the fact that jp-6 voice boards are used in the MKS-80 (two 4-voices, making it essentially a 8-voice jp-6 from the sound generation standpoint). It is even said that voice boards are interchangeable.
Clusterchord is a member of this forum who should be able to confirm/infirm that as I remember him to be very knowledgeable about the Jupiter and MKS series

Xavier