JX8P problem, wonder if MI community can help?

Seems to work after wiggling the jacks so I just assumed it was the jack hah.

Sounds reasonable…

Ive been using a BCR2000 to work around it but i would still like to replace the slider eventually. is the data slider the same as the volume slider?

http://www.vst-control.de/JX-8v.html I highly suggest this.

$30 is overpriced when other options exist

Which other options?


The JX8P parameters can be controlled over MIDI using SysEx messages. I built a controller for mine using an Arduino. The advantage of this is you can do cool stuff not possible normally, like code a triangle wave LFO in software and route it to whatever parameter you want.

Here’s a question I asked on SO regarding the messages when I was making it.

And a dude posted all the parameters you need to control different things via sysex.

Probably the volume pot (slider) is logarithmic, while data pot (slider) is linear.
Q:Can I order parts from Roland directly?
A: Yes! Roland has a huge inventory of parts that can be ordered directly by calling our Customer Support department at 323-890-3740, Monday through Friday, 8:30am to 5:00pm Pacific Standard Time.

Roland US based has helped me countless of times, the German based as well.
Call them, ask them, that would be the first and best option to try for (you) me.
Their prices + shipping are reasonable.

If they don´t have your data slider, call Roland in Canada, as dude163 suggested at: “604-270-6626 ext 108”.
If they don´t have your data slider, then post here a picture of your slider with every possible dimension between posts, pins, height(s) from base + slider tip, width, length(s), etc.

alright thank you very much everyone! i will definatly take your suggestions and hopefuly find a replacement. im rather busy this week so its not my first priority but i will let you know how it goes, thanks again!

I just fixed my parameter slider and also Bend Range by desoldering it and cleaning it it now goes from 0 to 99 without jumping :slight_smile:

@jackdamery thats great! was it a long process? i messed up my first build and have been discouraged from attempting more soldering.

@Gnome. Sorry I only just saw your reply. No, it took maybe two hours tops. The process is something like:

1. Unscrew screws on endblocks of JX8P and pop the lid.
2. Photograph the positions of the connectors to the board with the edit sliders.
3. Unscrew the board (keep screws safe) and disconnect the connectors.
4. Mount the pcb to some helping hands or bluetack it to the table etc.
5. Heat up soldering iron and while waiting choose a slider to remove.
6. Lay solder wick on the largest lugs in the middle, one at a time. Gently press the soldering iron on the top of the wick where the lug is soldered for a couple of seconds until it draws some solder up. I tend to use a lot of wick, i.e. use a new section of wick for each application of the iron to the joint. Make sure to wick the solder below the lugs where they are bent to prevent them lifting the solder pads.
7. Using a thin flathead screwdriver gently bend the lugs up so they are straight and can be pulled through.
8. Repeat this for the connections at the end. It will take some gentle wiggling to get them to come out, but if you have removed ALL the solder it shouldn’t be too difficult.
9. Now you have the slider removed from the board use your thin flathead screwdriver to bend up the clips that retain the bottom plastic part to the metal top. Take not of the orientation of the slider to the top part as it’s possible to get it the wrong way around.
10. Open up the slider and clear out the 20 something years of crap. Make sure to get it all. Use a PLASTIC tool like a piece of an old credit card if you need to scrape off built up grease.
11. Put the slider back in place and bend the retaining clips back in place. If you want, verify it’s working well with a multimeter.
12. Replace the slider on the board and bend the lugs back in place using a flat metal edge.
13. Resolder all points.
14. Reconnect all connectors and screws.
15. Close lid and screw it down.
16. Rejoice that you can now edit parameters properly.

RE: Soldering - Maybe practice on some cheap Velleman kits. Watch some tutorials so you know what you should be doing and get a cheap temperature controlled soldering iron with a thin flat tip.


@jackdamery THANK YOU! thank you a ton for your walkthrough. i havent tried this yet as ive been extremely busy and stressed out for the last while but hopefully i can attempt this at some point. at the moment all my synths are in cases and i havent even been able to play music for the past 6 months but im going to make more of an effort to get things moving again.

I too have been experiencing this issue for a while with the Edit slider.

I have found a service manual online for the JX8P which indicates that the volume, After-touch, Edit & Portemento are all the same part number (here is the service manual- see page 1- http://manuals.fdiskc.com/flat/Roland%20JX-8P%20&%20PG-800%20Service%20Manual.pdf)

I’ve looked at the Syntaur photo of this slider (https://syntaur.com/images/1426-Lg.jpg) and it clearly indicates that the slider is a 10Kohm, additionally, their text (https://syntaur.com/Items/1426.html) indicates that the art is a 30mm slide.

Has anyone looked for acceptable alternatives? Mouser Electronics lists 28 matches when searching for a similar slider (search criteria: 10kohm, 30mm- http://www.mouser.com/Passive-Components/Potentiometers-Trimmers-Rheostats/Slide-Potentiometers/_/N-9q0yl?P=1yzogluZ1yzmno7)

There are several in that mouser list that CLEARLY are not the correct item.

My next step is to try to “clean out” the existing part in my synth.

Any input would be appreciated.


A simple swap like that should work. Just make sure that the pinouts are wired to the right areas of the PCB.

As a software alternative, you should look at the free Ctrlr program that already has a JX8P editor built in.

Just add a touch screen, and that is way better than owning the JX8P hardware programmer. Trust me a box full of these sliders sucks just as much as you think it would.

@audiohoarder this seems to be the most approachable solution if you aren’t partial to soldering. i ended up using the behringer bcr2000 as an alternative but for some reason one of two of the parameters dont seem to respond. most of it works well though.
as for a touch screen, not a big fan of apple so i suppose in the future i could look out for a cheap tablet.
for now though ive been renovating so everything is put away or against the wall. unfortunately i need dustcovers and more cases so the majority of my equipment is covered in a thick layer of dust which is really dis-heartening…

@Gnome:You can get a Windows 8 laptop with a ten point touchscreen for around 300- 350 USD. Not cheap, but the upgrade to Windows 10 for a year. I do not recommend the BCR 2000 they all seem to die randomly.