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Jupiter-6 Restoration Project Log

Posted: Sat May 26, 2007 3:59 pm
by StepLogik
Well, since my bargain priced JP-6 didn't sell, I figured I might as well go ahead and restore it. While I am at it, I think I'll do some custom mods as well. Specifically, a custom repaint of the front panel and wood end caps. The front panel has some minor scratches which have rusted, so I'm probably going to sand the front panel down before its painted.

If it turns out I need to replace the sliders, then I'm going to ship just the panel boards (there are 2, 3 if you count the bender board which has 2 sliders) off to a tech and also have the LED's converted to blue ones. $$$$$

So, I decided to start by replacing the missing IEC power connector - something even I could repair. So I opened up the JP-6 and HOLY s**t what a mess. The inside was FILTHY and rusted out. The boards and electronics are in great shape, but the chassis is stained and rusted.

The inside is clotted with cat hair, pubes, mcdonald's fries, gum wrappers, dust and dirt, rust, and various other debris. Just cleaning out all that c**p out will be quite a chore.

Here are some pix of the guts of the JP-6 BEFORE cleaning:

http://home.comcast.net/~derekcj75/gear ... -r-002.jpg
http://home.comcast.net/~derekcj75/gear ... -r-003.jpg
http://home.comcast.net/~derekcj75/gear ... -r-004.jpg

Here is the rusted underbelly of the keybed:

http://home.comcast.net/~derekcj75/gear ... -r-001.jpg

The contacts are actually in pretty good shape, but i'll certainly clean them up while I've got it apart.

Next Steps:
-------------
1) Remove Right panel board, power switch, jack board
2) Vacuum out all the dirt and grime and clean up the rust
3) Remove bender board from the left panel assembly
4) Ship front panel, bender panel, and right trim piece to Custom Synth for new graphics

Posted: Sat May 26, 2007 4:59 pm
by Tardis
Cool! Another synth resto project.
You'll finish your Roland project before mine is done lol!
Any other pic's?

Posted: Sat May 26, 2007 5:01 pm
by StepLogik
Tardis wrote:Cool! Another synth resto project.
You'll finish your Roland project before mine is done lol!
Any other pic's?
i should have some more soon -- i'm removing more bits now

Posted: Sat May 26, 2007 5:45 pm
by StepLogik
Well I've hit the first major snag... I can't remove the pitchbend assembly from bender panel assembly. The screws are glued in order to lock them place. If I really bear down with a screwdriver, they are just going to strip.

Anyone have any ideas for dissolving that glue?

After that I suppose a little WD-40 should loosen up the screws a bit

Posted: Sat May 26, 2007 6:11 pm
by Tardis
Acetone on a Q-tip...

Posted: Sat May 26, 2007 7:24 pm
by StepLogik
More pix... Here is the lower chassis with the 2 module (sound) boards, the CPU board, and the power supply and RF Filter board. The jack board is hanging off to the left:

http://home.comcast.net/~derekcj75/gear ... -r-005.jpg
http://home.comcast.net/~derekcj75/gear ... -r-006.jpg

The raw boards for the controls:

http://home.comcast.net/~derekcj75/gear ... -r-007.jpg

Main panel:

http://home.comcast.net/~derekcj75/gear ... -r-008.jpg

Time to ship that panel off to Custom Synth UK!

Posted: Sat May 26, 2007 8:25 pm
by StepLogik
Interesting bit of JP-6 trivia: There are two module boards that make the sound. Each board can do 4 voices. On the second module board, only 2 of the voice channels are populated. Same board and same layout except for the missing components.

Also, each board has a slave CPU which is a bit interesting. Effectively there are 3 CPU's in the JP-6. I suppose it was cheaper to delegate responsibility to slave CPU's than to try and put 1 badass CPU in there and let it handle everything. I'm curious what the protocol is between the main CPU and its two subordinates - I'm guessing some type of serial line.

It might also be interesting to see if you could slap a fully populated voice board in place of the half-populated one and see if you get an 8-voice JP-6. I would imagine the voice allocation code in the firmware would have to be hacked in order to make it work. But, it would be fascinating if each module board's CPU reported its voice capability (2 or 4 voices) to the main CPU during boot so that it could adjust the voice allocation algorithm accordingly. But, considering how awful the Roland firmware code is (based on the europa project's analysis of it) I would say this very unlikely.

Posted: Sat May 26, 2007 10:37 pm
by neandrewthal
Thanks for the pics. If you don't mind me asking, which are the VCO chips? Voice 2 of osc 1 is busted on mine and I need to drop a new one in (I have it, but I don't want to remove it from it's anti-static bag just yet)

Posted: Sun May 27, 2007 12:27 am
by StepLogik
dougt wrote:You would need to rewrite the entire OS to support 8 voices... All the extra chips and other parts wouldn't be cheap either...

Not to put Europa in it while you're doing all this would be a shame... :)
Its already got the Europa mod, thank goodness.

Hey dougt do you have a 100K rotary pot for the JP-6?

Posted: Sun May 27, 2007 5:01 pm
by StepLogik
The knobs on the JP-6 are uglier than a cat's asshole. I'm definitely getting rid of them and using some really nice, classy metal knobs.

Not sure what to do about the slider caps. I'm going to dye them a different color, but I haven't decided that yet either. I might use different colors for different panel sections to give it a bit of color (like the JP-8's buttons) but that could get kinda corny if not done tastefully.

Picked up some acetone today to try and dissolve the threadlock glue on the pitch bender assembly screws.

Does anyone know of anyone else that does custom panel graphics like Custom Synth? I need a contingency in the event they can't take the job (sent an email so hopefully I will hear back from them soon).

Posted: Sun May 27, 2007 7:03 pm
by Tardis
StepLogik wrote:Picked up some acetone today to try and dissolve the threadlock glue on the pitch bender assembly screws.
It takes a few applications, but it will totally dissolve the thread glue.
StepLogik wrote:Does anyone know of anyone else that does custom panel graphics like Custom Synth? I need a contingency in the event they can't take the job (sent an email so hopefully I will hear back from them soon).
I had a hard time getting local shops to take on my SH-1000 panel graphics. That's why I went to Jeff (Custom Synth).
Just be patient, he'll get back to you. He's a good guy to deal with.

Posted: Sun May 27, 2007 10:20 pm
by nathanscribe
This is fascinating. Good luck with it!

Posted: Mon May 28, 2007 2:13 am
by Blue Monster 65
Good luck, SL! Always good to see someone undertaking these projects.

By the way, you do realize you can hack the shaft off to size, right? Grab it and go.

Woof! - Scott

Posted: Mon May 28, 2007 2:30 am
by StepLogik
neandrewthal wrote:Thanks for the pics. If you don't mind me asking, which are the VCO chips? Voice 2 of osc 1 is busted on mine and I need to drop a new one in (I have it, but I don't want to remove it from it's anti-static bag just yet)
Honestly, I have no idea. I'm trying to track down a service manual for the JP-6 so I can calibrate / tune-up and make sure the power supply rails are still up to spec. When I get one, I'll let you know.

Posted: Mon May 28, 2007 2:53 am
by Blue Monster 65
I'll be in the shop Tuesday night. I'll look for a repair manual/schematic then.

Woof! - Scott