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 Forum index » DIY Hardware and Software
Roland JX-8P restoration
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LektroiD



Joined: Aug 23, 2008
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PostPosted: Mon Dec 16, 2013 12:51 pm    Post subject: Roland JX-8P restoration Reply with quote  Mark this post and the followings unread

A few things are wrong with this synth:

The keyboard has hanging notes. It seems to be the same notes every time, so it is probably dirty contacts. This is the later JX model, and has the same weighted keyboard as the D50. Earlier JX models had the same keyboard as the Juno 106, I have a full 106 keyboard, so I'll see if I can swap them over.

Moving the data slider is like trying to drag Velcro over a carpet. I'm not sure what to clean it with, avoiding damage to the carbon track. Maybe a replacement would be a better option.

The display is intermittent (mostly off) - solder retouch should hopefully sort this

Noisy chorus. I'm not sure where the chorus circuit is on the PCB, but when I locate it, I'm thinking of swapping the old electrolytics for new to cure it, unless someone has a better suggestion? Failing that, I will just switch the internal chorus off and use an external.

That's all for now, I'll update with my progress as I get working on it.

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new voodoo



Joined: May 06, 2013
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Location: RVA USA

PostPosted: Wed Dec 18, 2013 1:23 pm    Post subject: Reply with quote  Mark this post and the followings unread

id DEF change the slider. Thatll b easy and cheap, its no problem to find slider pots/variable resistors etc almost anywhere.
I dunno what you mean by "electrolytics" but if the chorus uses a dedicated chip like a mn3207 or what-have-you..depending on the chip..yoou might be able to replace it.
That said, id be VERY careful messing around with an old PCB unless youve got a dope soldersucker thats self-heating, etc and have used it a good bit. using wick or some other method could easily destroy everything
I LOVE the jx-3p and if yoou can get the programmer (believe its the pg-1000? i know its the pg-200 for the 3p) its and incredible board-ive played a few 8ps but never owned one. its worth fixing up for sure.

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gdavis



Joined: Feb 27, 2013
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PostPosted: Wed Dec 18, 2013 2:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

pg-800 is for the jx-8p, pg-1000 is for the D50.

I removed and dismantled all the sliders in my Juno 106 to clean them. Tedious but not difficult and they all work great now with no problems. I thought I read somewhere that correct replacements were hard to find, don't know if the jx-8p uses the same ones or not. There's a whole bunch of videos on youtube from a guy restoring 106's, one of them goes into detail on cleaning the sliders, shouldn't be hard to search and pretty informative.

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Skrog Productions



Joined: Jan 07, 2009
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PostPosted: Sat Dec 28, 2013 3:10 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Rich , merry xmas Smile

Sounds an interesting refurb your doing with a JX8P , is it a kinda fader less juno 106 sound wise ? , good addition to your studio when fixed Smile

Dave.

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LektroiD



Joined: Aug 23, 2008
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PostPosted: Wed Jan 08, 2014 9:04 am    Post subject: Reply with quote  Mark this post and the followings unread

Skrog Productions wrote:
Hi Rich , merry xmas Smile

Sounds an interesting refurb your doing with a JX8P , is it a kinda fader less juno 106 sound wise ? , good addition to your studio when fixed Smile

Dave.


Hey Dave,

All working now, just requiring the 10K data entry & volume sliders, although they seem pretty hard to source, loads of close matches around, but can't find any that will fit this.

Anyway, I have to say, it's way better than the Juno series in many respects, it has 2 oscillators for a start, then there's all the cross modulation, unison modes, etc. Sounds way better than any juno I've owned.

Why not pop over and have a listen yourself sometime, I'm only up the road from you...

Rich

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new voodoo



Joined: May 06, 2013
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Location: RVA USA

PostPosted: Tue Jan 14, 2014 12:23 pm    Post subject: Reply with quote  Mark this post and the followings unread

if yr still haveing problems i can send you a list of sources for vintage parts that I use. You may find one or two youre not aware of.
Have you tried Leeds Radio in Brooklyn NYC or Vintage Planet?
I dnt do a lot or repair per se but I take apart virtually everything and mess with it.

Which is quite possibly a disease. but at any rate as a result i often have to find unusual things.

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-oddities & weird
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-bending DIY/projects
-crap
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