My next fixer-upper - JX-8P

Discussions about anything analog, digital, MIDI, synth technology, techniques, theories and more.
User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

My next fixer-upper - JX-8P

Post by Synthaholic » Thu Feb 07, 2008 10:00 pm

UPS dropped this off yesterday:

Image

Functionally it's great, it just needs some keybed work, slider caps, and a good cleaning. 2 keys are broken. The piece of tape is holding the broken black key up so it doesn't cause a stuck note.

Here it is with my other fixer-upper, still hunting down voice chips for the Juno:

Image

BTW, if anyone has any extra slider caps for the JX-8P, or a PG-800 they're willing to part with, let me know...
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

User avatar
Box
Senior Member
Senior Member
Posts: 772
Joined: Wed May 02, 2007 1:07 pm
Gear: Roland JP-8000
Roland JX-3P
Roland JX-8P
1972 Wurlitzer Console Piano
Band: Neo Decorum
Location: Land of oscillators, filters, and other really cool looking stuff.

Post by Box » Thu Feb 07, 2008 10:39 pm

Good luck on that. JX-8P is a great synth. I had opened mine up and cleaned it awhile back. 20 years of dust, hair, and the occasional cat claw. I managed to regain some of the after-touch, just need to do a serious cleaning on it; then again I never use after-touch. But the sounds you get are mind blowing. I find myself using it more than the Ion now even though the Ion far surpasses in capabilities. I've always wanted a Juno but the dead voice has always scared me, so guess 60 would be the way to go. So how are you enjoying them now, disregarding the faults?

Btw, you really don't need the PG-800, everything is easily edited via the single slider. Something about paying more for the programmer than what I did on the synth seems a little crazy.
Image
Help our very own Maschinengeist (Stéphane) by making your next purchase or repair with him! Click the logo for more info!

User avatar
Yoozer
Expert Member
Expert Member
Posts: 1390
Joined: Sun Oct 09, 2005 1:31 pm

Post by Yoozer » Thu Feb 07, 2008 11:09 pm

In the trio of the Juno-60, JX3P and JX8P the 8P is rather modest and melancholic. The others are richer and brighter; the 8P excels at the moody pad sounds and occasional surprises (bass sounds that go whomp).
"Part of an instrument is what it can do, and part of it is what you do to it" - Suzanne Ciani, 197x.

User avatar
crystalmsc
Synth Explorer
Synth Explorer
Posts: 2860
Joined: Thu Jul 13, 2006 7:15 am
Gear: uWaveXT,uQ,Pulse+;Ion;MiniBrt,Karma,Mntrb,Volcas,01R;Venom,NordModular,L2X;Evolver;JP8080,MKS70,JD990,D50,MC909,MC80ex,Microcon2;TG77,RS7k,AN200,AN1x
Band: Crystaline
Location: Synth Garden
Contact:

Post by crystalmsc » Fri Feb 08, 2008 9:04 am

hope that the DCO beast get well soon, is worthy.
Kaossilatron - Voicillator
http://crystaline.bandcamp.com
Station: Ableton Live 10 Suite, Obscurium, Push 2, Ultranova, MS-20m, Wavedrums

User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

Post by Synthaholic » Fri Feb 08, 2008 2:29 pm

crystalmsc wrote:hope that the DCO beast get well soon, is worthy.
Which one? They're both DCO beasts... ;) Or did you mean "hope that the DCO beasts get well soon..."
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

User avatar
crystalmsc
Synth Explorer
Synth Explorer
Posts: 2860
Joined: Thu Jul 13, 2006 7:15 am
Gear: uWaveXT,uQ,Pulse+;Ion;MiniBrt,Karma,Mntrb,Volcas,01R;Venom,NordModular,L2X;Evolver;JP8080,MKS70,JD990,D50,MC909,MC80ex,Microcon2;TG77,RS7k,AN200,AN1x
Band: Crystaline
Location: Synth Garden
Contact:

Post by crystalmsc » Sat Feb 09, 2008 4:44 am

Synthaholic wrote:Which one? They're both DCO beasts... ;) Or did you mean "hope that the DCO beasts get well soon..."
it's for the JX to me :wink: a monster beast for the JX10/MKS-70 and a sweetheart for the Juno :) both are a nice pair.
Kaossilatron - Voicillator
http://crystaline.bandcamp.com
Station: Ableton Live 10 Suite, Obscurium, Push 2, Ultranova, MS-20m, Wavedrums

User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

Post by Synthaholic » Mon Feb 11, 2008 10:22 pm

I had the JX apart the other day, giving it a "bath".

So far, I cleaned the entire inside and outside of the case (lots of dust bunnies and a dead fly or two inside), cleaned all the key contacts (all the keys respond great now), and temporarily replaced the broken black key with an extra Juno-106 key (same construction but no weight inside) so no more note getting stuck on when the key "falls down". The broken white key still works fine, so I'll wait until the real deal replacement arrives.

Image

Image

Image

Image

I'm still looking for 2 more slider caps, if anyone has spares. I also need to do the aftertouch fix, but I'll wait until the replacement keys arrive and do everything at once.

Other than the broken keys, the synth is functionally perfect. One of these days I'll try programming a few sounds to see what it's capable of. I try not to get too attached to my fixer-uppers though, since my wife doesn't want me keeping them. My rig does need a real analog though. ;)
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

User avatar
Mr. Black
Junior Member
Junior Member
Posts: 161
Joined: Mon Jan 08, 2007 12:34 am
Location: New York, USA

Post by Mr. Black » Tue Feb 12, 2008 3:00 am

:thumbright: Nice work !! I had to clean a couple of D50 key's to fix the velocity and sell it,I hate opening and taking things apart,not my thing, i don't even like looking at the gut's of classic synth's strange how it does not appeal to me,I accually had my girlfriend help me so i could remember what i was doing,she thinks I'm crazy!!.

User avatar
crystalmsc
Synth Explorer
Synth Explorer
Posts: 2860
Joined: Thu Jul 13, 2006 7:15 am
Gear: uWaveXT,uQ,Pulse+;Ion;MiniBrt,Karma,Mntrb,Volcas,01R;Venom,NordModular,L2X;Evolver;JP8080,MKS70,JD990,D50,MC909,MC80ex,Microcon2;TG77,RS7k,AN200,AN1x
Band: Crystaline
Location: Synth Garden
Contact:

Post by crystalmsc » Tue Feb 12, 2008 3:49 am

Synthaholic wrote:I had the JX apart the other day, giving it a "bath".
looking good so far man, salute to all synths manintenance around the globe :) those babies deserved that. I remember opening the U-220 and Wavestation to clean it up inside out, the result was very satisfying. One lit'l trick to share is the Cajuput oil is mostly effective in cleaning the body of the synth or the ex-sticker dirt.
Synthaholic wrote:Other than the broken keys, the synth is functionally perfect.
that sounds great, hope all fully working soon.
Synthaholic wrote:One of these days I'll try programming a few sounds to see what it's capable of.
try to make some pad, it's hard to make it sounds bad..you'll love it.
Synthaholic wrote:My rig does need a real analog though. ;)
you bet..or to me, my rig always need a JX :lol:
Mr. Black wrote:I accually had my girlfriend help me so i could remember what i was doing
oh, she is nice :)
Kaossilatron - Voicillator
http://crystaline.bandcamp.com
Station: Ableton Live 10 Suite, Obscurium, Push 2, Ultranova, MS-20m, Wavedrums

User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

Post by Synthaholic » Tue Feb 12, 2008 2:14 pm

I was playing with the JX last night. I downloaded a free PC editor so I could play around with the programming. I still would want a PG-800, using a mouse to grab "sliders" just isn't the same. Or I need a laptop with a touch screen. ;)

While playing with it, I discovered the mod lever on the pitch bender isn't working. It was working before, so something must have happened when I was doing my cleaning. Oh well, something else to figure out next time I open 'er up. Maybe a connector is loose or something.

EDIT: Figured out the mod lever problem last night. Turns out the editor I'm using is setting the mod depth parameter to zero. What's funny is the editor (which mimics a PG-800) doesn't even have this parameter available to edit, I have to edit it on the synth itself. So I wasn't even aware that parameter exists, but now I know how to fix it. ;)

I cleaned the LFO mod button anyway. ;)

Why oh why doesn't the JX have PWM?? :?
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

MarkShovel
Newbie
Newbie
Posts: 66
Joined: Tue Feb 21, 2006 10:12 pm

Key Contact cleaning comment

Post by MarkShovel » Wed Feb 13, 2008 7:05 pm

Please elaborate on you comments about the key contact cleaning. What problems were you having and how did you fix them?

I've got two JX-8Ps and a JX-10.

Mark
A6 2 V-Synths VC-1 VC-2
OB-Xa OB-8 two Matrix-6 Matrix-1000 DX
Fantom X8 Waldorf uWAVE XT
JD-800 JP-8000 XP-50 Juno-60
JX-10 2 JX-8P's w/ 1 PG-800
2 JX3P's w/ 2 PG-200s
Moog Opus-3 Boss DR-770
21 guitars 3 Marshalls

User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

Post by Synthaholic » Wed Feb 13, 2008 7:33 pm

Some keys weren't responding consistently when played, until I cleaned the contacts.

Erratic velocity sensing (keys responding at max velocity even when pressed slowly, or one key being more velocity responsive than another) can also be caused by dirty contacts.

Aftertouch is another issue entirely. This weekend I hope to remove all the keys and clean the aftertouch strip so it works better.
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

MarkShovel
Newbie
Newbie
Posts: 66
Joined: Tue Feb 21, 2006 10:12 pm

cleaning technique

Post by MarkShovel » Wed Feb 13, 2008 7:48 pm

Thanks,

So how did you clean the contacts? Air to blow out the dust? Isopropal alcohol?

Mark
A6 2 V-Synths VC-1 VC-2
OB-Xa OB-8 two Matrix-6 Matrix-1000 DX
Fantom X8 Waldorf uWAVE XT
JD-800 JP-8000 XP-50 Juno-60
JX-10 2 JX-8P's w/ 1 PG-800
2 JX3P's w/ 2 PG-200s
Moog Opus-3 Boss DR-770
21 guitars 3 Marshalls

User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

Re: cleaning technique

Post by Synthaholic » Wed Feb 13, 2008 7:54 pm

MarkShovel wrote:Thanks,

So how did you clean the contacts? Air to blow out the dust? Isopropal alcohol?

Mark
Nothing so high-tech. ;) Actually I took a q-tip, cut it in half, and taped a piece of copper desoldering braid onto the q-tip stem I cut. I then gently rubbed each contact with the braid. I figured that this would be abrasive enough to remove dirt but not enough to damage the contact points. Worked great. Alcohol would work but then I'd be concerned about residue, and by not using the cotton swab end of the q-tip, I wouldn't end up with cotton bits in the contacts.

If there's a lot of dust some air is good to blow it out. There wasn't a lot of dust in mine so I just used lung power. I removed the remaining dust with the q-tip and braid jig.
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

User avatar
Synthaholic
Expert Member
Expert Member
Posts: 1206
Joined: Tue Aug 21, 2007 5:43 pm
Gear: Motif XS6, TX802, D-550, A6
Location: NH

Post by Synthaholic » Sun Feb 17, 2008 3:50 pm

Some more pics of the fixer-upper being fixered-uppered:

Removing the keybed
Image

In case you ever wondered what a JX-8P main board looks like:
Image

Smokey inspecting my work
Image

I washed all the keys. Here's the white keys sorted and ready to be reinstalled.
Image

Reinstalling the keys. I put the blacks in first and am installing the whites in this pic.
Image

All keys reinstalled!
Image

And the synth is reassembled!
Image

Now if I could just find some slider caps.
Two VCO: thanks to the push rods, one can choose several forms of waves at the same time!
(from a Babelfish translation of a Jupiter-6 site)

Yamaha: Motif XS6, TX802 Roland: D-550 Alesis: A6 Andromeda

Post Reply