Many thanks to everyone in the Synthesizer community that make these projects worthwhile. Special thanks to Keith Meiere, Fred Vecoven, Jonathan Williams & Alex Bhinder for providing the instruments, support and enthusiasm to drive these projects.

Roland Keyboard Flexible Circuit

A new flexible circuit board for the Roland JD-800 and U-20 keybed. It will soon be time to fix your keyboard! We are planning to release this as a product soon provided that the next production run is successful.


First run was called “Version 2” as shown in the JD-800 fitting guide. It was used to test and gather data, it was 100% successful.

If you would like to be added to a priority list for when this product is available, please contact us for details at

Run number 2 was for Version 3 that contains silk screen improvement to aid reassembly and supports the Roland U-20, was tested during September 2021.


A production run has been ordered using funding from sales of SuperJX displays and the supply of the second run. They take the supplier 9 weeks to manufacture. Hoping that these will become available end of November 2021. There will likely be 2 quality levels at different prices. The target price is 160 GBP but this depends entirely on manufacturing yield, they cannot be electrically tested by the factory before they are delivered to us and the process can impact cosmetic quality of the contacts. Apologies for an indefinite price but these are very hard to manufacture.

Special thanks to everyone who supported this project.


Modern materials and manufacturing techniques make for an excellent replacement. The design employs gold plated contacts, Polyimide base layer and new transition PCB. Creating a flexible PCB of this length, more than double the usual standard of 450mm leads to significant challenges in manufacture and automated test.


To aid in the high costs of tooling a large flexible PCB, Jonathan Williams and PCBWay have sponsored and supported this project.

Special thanks to Jorick for being the first to try out the new PCB kit on the JD-800, he documented the details on his fabulous synthesizer blog.


Update August 31st

U-20 upgraded and fully operational. Instructions written and we just have cable build up to document on a web page. Performance is really quite lovely. Aftertouch also tweaked, modification method published.

U-20 KeyboardTest

Flexible PCB run 2 has arrived 2 weeks early and being tested and assessed very carefully. Some are cosmetically perfect, others are not, but yield is as expected at about 80%. We are half way through testing all of them by building into a real keyboard assembly.

Magnetic badges have been ordered so that synthesizers with Flexi PCB can be identified easily. More transition PCB and connectors ordered that will arrive in time for shipping first kits.

On target for starting shipping some kits in mid September to people who joined the list. A larger order will follow so that future customers won’t have to wait.

Testing of the new PCB version in Japan for the type 2 application has been successful! Identify yours as per picture below. Other variant is now covered!


Update July 31st

Today it was time to connect the flexible circuit to a U20 using the new transition and adaptor PCBs. It works but was a very difficult fitting due to awkward desoldering and fitting push fit pins to the PCBs.

Results however were great!


There are two methods of connection in the U-20, transition PCB or a very long and fragile flexible cable as shown in the picture below.


We have opted to make a replacement cable and adapt the connectivity using a PCB attached to the motherboard.

Pictures below show how this was achieved. Really good desoldering skills are required because motherboard traces around the old connectors are very thin and their holes are very narrow. It really wasn’t easy, despite how it looks in the pictures. The other issue is the wiring layout of the U-20, it is a diabolical array of wire to board connectors making it extremely tricky to manage. “Value Engineering” is taken to extreme in this Roland design.

Space is tight but it works well, the transition PCB has been adapted so that it can be mounted on the keyboard frame with 3 X 17mm M3 spacers. The Aftertouch connections are not used and a 30 way right angle IDC header is fitted.

Update July 18th

The Roland U-20 keyboard repair has started. This instrument has suffered red death, interconnect failure and all manner of issues from “tinkerers” doing a bad repairs. It’s previous owner had it scheduled to replace a keyboard assembly inside a Roland JD-800 but luckily the Red death hit the keyboard assembly before the transplant got underway….. And it ended up here as a result, saving another synthesizer from doom!


This is a pretty exciting spin off project because the Roland U-20 deserves some love, despite not having a filter and being a “Rompler”! It oozes 90’s dance music.

Also updated this week is the fitting guide with a funky new method of safely removing the rubber contacts.


Inspired by a beta tester, Carsten, we use a silicone sealant tip to push over the pillar before gently pulling it from the contact side.

Update July 11th

All feedback received from adopters and (hopefully) final design definition PCBs ordered at version 03. Now we test design for manufacturing.

New transition PCB designed and ordered that accommodates Roland Flexi type 2, where connections on white flat cable are on opposite side. The interesting part of the puzzle is that the black connector needs rotating 180°. Below is a picture of the flexible PCB that Roland fitted to the later run of instruments and supplied as a spare, many thanks to Ryan for providing initial data on this. We’ll be doing a trial fit in Japan in a few weeks.


Update June 21st

Early adopters have provided feedback and the fitting guide has been improved to include more detail in areas where the service manual is not clear.

Development of a transition PCB set to work with the Roland U-20 continues and boards have been ordered.

U-20 Keyboard Development

Version 3 flexible PCB has new features for accommodating the Roland U-20, hopefully will be ordered soon.

One thing that was noticed was that every single 10uF capacitor in the U-20 mainboard had leaked it’s contents, a huge job awaits getting this synth up to the standard it was when new.

The U-20 synthesizer will become a test and reliability platform for the new keyboard replacement PCB kit and will be available if required.

Update June 3rd 2021

First build of PCBs have been released to people for first trials.

An interesting study of failure modes of the keyboard assembly has been written that explains all details of what and why you get performance degradation.


10th May 2021

It functions perfectly, fits nicely and more tolerant of worn rubber contacts. Gold plating and careful diode selection has been verified to make the keyboard much more tolerant of worn and damaged rubber contacts.

More test instruments found and being upgraded….. including U20, D5 and a JD800 in probably the worst condition we have ever seen. These will definitely prove the design as we don’t intend to replace the old rubber contacts.

Fitting guide is complete 👍


First run of 9 or 10 is being hand built, they will be released in second week in June. The connection lead is a little longer than it should be, accommodated by a small piece of insulation tape on base panel. Laser trimming was not available, so we cut the mounting slots ourselves.

Contact us to register interest in the first or second run. Second run will be 6 to 9 weeks leadtime after first run has gone. Unlike normal rigid PCBs, they have a complex manufacturing process so take longer.

April 28th 2021

First samples have arrived. Mechanically fits ok, built in tolerance avoids issues, first sample needs slotted guide holes trimming as we didn’t pay extra for cutting.

They do look fantastic with gold plated contacts.


Next steps: Design test equipment to confirm all contacts, connections and vias. Obtain spare metalwork for fixturing and checking purposes. Write a fitting guide whilst rebuilding the first keybed.

March 15th 2021

The task of measuring a sample keyboard contact arrangement and subsequent PCB design is completed. Engineering drawings, cutting and track placement data collected and submitted. Various complex manufacturing issues were discovered, a guide to producing complex data pack for this project was shared on the PCBWay website to help other engineers produce flexible circuit designs.

A guide showing the technicalities of making Flexi circuits with free tools is here

All enquiries contact Guy Wilkinson at:


JX-8P OLED Display

A spin off from the JX-8P Vecoven Flash project and JX-10 replacement display, it enhances the display significantly when used in conjunction with Vecoven upgrades. Compatibility is provided for other firmware and even other instruments that use the same NEC controller in one line mode.

Testing completed, instructions written and first build of 6 has been completed, orders can be shipped.


February 2021 – Manual Ready & Testing Almost Complete

A huge amount of progress made coding special screens with a small modification to the Vecoven SuperJX Flash Firmware to add extra functionality.


Great care has been made to ensure that the replacement emulates the old display with nearly all supported commands and features with a 16 x 1 character emulation.


Only marketing data now needs to be completed.

January 2021 – Software Completed

Design of new layouts for extensions when using Vecoven SuperJX Flash module.

Next steps are to write an installation manual, update website and show some pictures.

Almost ready for release!

December 2020 – progress on software

  • JX8P 6303 & pic18f display code running under an emulator and virtual machine, with OLED and VFD hardware emulated in Java
  • Build variants for JX8p and JX10 on display code.
  • Prototype installed in an instrument, basic Roland mode works perfectly.
  • New PCB that has fitment options for all SuperJX and 8P versions has been ordered.
  • Bootloader for reflashing when using with new Vecoven firmware.


November 2020 – progress on software

  • JX8P display protocol added to SuperJX display code base allowing different build versions.
  • JX8P version has access to all SuperJX display software features including OLED/VFD compatibility with it’s bitmap fonts, layouts and character displays.
  • Plan is to extend the display arrangement when using Vecoven SuperJX Flash.


Picture above shows software being tested with VFD in it’s character mode. All other modes were tested including graphic.

It is a shame that in the JX8P, replacement VFD will not fit inside and power supply is too weak. It could be addressed with a new display board or some advanced mechanical modification.

October 2020 – progress on test board

  • Software protocol handler written
  • Further display chip commands discovered and analysed: All Roland VFD displays understood


September 2020 – significant progress made:

  • Test software written that exercises every function and performance of the original Roland design
  • Specification written that describes all the technical details including timing & commands
  • Test set updated to test production displays

August 2020 – Explore Possibilities & Displays


The picture above is from some concept work done by Guy Wilkinson and Jonathan Williams. It just shows the “Splash screen” for JX10 for basic testing of what is possible with the window, apologies to Fred for cutting off his name, see second picture!


The mechanical design is especially difficult due to very precise tolerance and limited space behind the bezel, it needs to look straight whilst being easy to fit.

D50, DX7IIFD, DX5, M1 OLED Displays

This is the same display as used in the JX10 and MKS70 OLED kits.

Instruments require de-soldering and soldering plus front panel disassembly. Korg M1 kit available that doesn’t require soldering.

Completed for D50, DX7IIFD, DX5, M1, MKS-80 and available here.


Power Supply Overvoltage Protection Measures

A number of reports are coming in where power IC M5230L reference circuit fails. When it does, it puts 44v across the analogue circuits and 7v on the logic causing damage.

A couple of component additions to existing PSU are being worked out using additional components to try and limit damage.


MKS 70 Gate Array Replacement

A spin off project from above when debugging a faulty MKS 70 at Plasma Music.


A PCB has been designed that replaces obsolete components on the assigner.

It also means that reliability of the MKS 70 is better assured and could be a donor instrument to fix a JX 10.



To help debug faults before changing the IC, some gate array test software is being written.

An EPROM can be installed that runs tests on the gate array functions and reports where faults exist either through bad connection, external RAM or IC itself.

August: Sample PCBs ordered ready made from PCBway!

September: PCB samples ready & donor MKS70 arrived for testing

October: Hardware tested & proven

Xvive Audio Chorus Chip Trial

Spotting the tell tale signs of noise and periodic interference of old devices followed by a test of the Xvive Audio chip to replace the Mitsubishi BBD IC MN3009.

Article will show replacement of the devices in a SuperJX.


Completed and can be seen here.

Copyright © 2020 Super Synth Projects, Guy Wilkinson