This page contains JX-10 and MKS-70 information about;
FAQ ‑ Manuals, Service, ROM IC Updates, SysEx, M‑64C Cartridge Copy Functions
SPECS ‑ Dimensions, Power Specs, Audio Output, Accessories
SLIDERS ‑ Everything About These Hard‑To‑Find Parts
ACCESSORIES ‑ PG‑800, M‑64C Cartridge, Cartridge Battery, Pedals And More
SAVE PATCHES ‑ SysEx Procedure To Save All Patches And Tones
POWER SUPPLY ‑ Tips For Repairing Or Replacing A Super JX Power Supply
TACT SWITCHES ‑ Unresponsive Front Panel Buttons? Replacement Tips & Part#'s
MISCELLANEOUS ‑ JX‑10 Drain Bamage Porblemz
ERROR MESSAGES ‑ Common Error Messages And How To Troubleshoot Them
JX-10 AFTERTOUCH ‑ Solutions For Restoring Or Replacing The Aftertouch Strip
BIRTHDAY DECODER ‑ Find The Birthday And Production# Of A Super JX & Other Roland Gear
EDITING SHORTCUTS ‑ Editing Tones, Patches, Global Parameters & Split Points
FUSE REPLACEMENTS ‑ Fuse Reference For Roland Samplers And Synths
CARTRIDGE PROBLEMS ‑ DIY Solution For Cartridge Problems
ODDBALL POWER CORD - Get Rid Of That Boondoggle!
DISPLAY REPLACEMENT ‑ Super High Quality Display Replacement
BATTERY REPLACEMENT ‑ Detailed Guide For DIY Enthusiasts
ENCODER REPLACEMENT ‑ Low Cost Encoder Replacement For The JX‑10
BINAURAL AUDIO OUTPUT ‑ Clever Ways To Use The Parallel Audio Output Jacks
RESTORE FACTORY PATCHES ‑ SysEx Procedure To Reload Factory Patches & Tones
POWER SWITCH REPLACEMENT ‑ Don't Pay Exorbitant Prices
FAVORITE DIY TOOLS AND DIY VENDORS ‑ Tips For DIY Freaks Who Like To Save Big $$$
SuperJX‑flash Upgrade Available!
And... A New Upgrade For It's Little Brother, The JX-8P!!
This is the pinnacle of Super JX upgrades. The 1980's meets the 21st Century! This new board is easy as popping in an IC chip and is an unbelievable piece of technology. It allows you to update the firmware on your JX‑10, MKS‑70 or JX‑8P using only MIDI cables! Daaaauuuumn! Now that's a cool invention!!! It also gives you access to 32 banks of cartridge data which is like having 32 M‑64C cartridges onboard all the time. Unreal! No more EPROM's are needed for firmware updates. Just send a *.SYX file to the synth
This thing is amazing! The JX‑10 just got bumped up to a higher level for professional musicians. Plasma Music Limited makes this incredibly responsive AT Strip & FSR Interface PCB. I have installed this on my JX‑10 and there is no comparison between this new one and the crappy factory installed AT Strip. I highly recommended this upgrade
I think these two topics are important enough to place at the top of all my synth INFO webpages
1) I buy a lot of broken synths on eBay and I'm able to fix about 90% of everything I find. It's usually a simple fix. If you have a synth with no power or intermittent problems after it warms up, it's probably due to the fact that back in the 1980's Roland and other synth makers used sub‑par solder and/or not enough solder to hold components in place. After 30+ years, the solder begins to break down and hairline fractures appear. This occurs at a higher rate for components which generate a lot of heat like Bridge Rectifiers, Power Transistors, large Electrolytic Capacitors, power input jacks and audio sockets which get a lot of use. The best approach is to use a magnifying glass and carefully inspect the backside of the circuit board. If you spot any suspect areas, re‑flow a hefty amount of NEW solder
2) I receive a lot of eMails and field many questions at synth related forums and also on Facebook. The most common question I get about problems with a synth has to do with errors when trying to load Patches and Tones. About 99.9% of the time, the problem always turns out to be a crappy MIDI interface. If you have a cheapo MIDI interface which looks similar to the one shown on the right... throw this piece of shit in the trash! Do It Now. Seriously! This thing is total junk and you get what you pay for. Inexpensive MIDI interfaces like this are unable to properly regulate the buffering of MIDI data. They will work fine with simple messages such as CC, Note On, Note Off, etc... however, when you try to send SysEx messages which are much longer, the SysEx data cuts off after only sending a few bytes. Investing in a higher quality MIDI interface will solve Load/Save errors and other communication problems. Also, if you experience errors when transferring Patch and Tone data from a computer to a synthesizer, DON'T use a USB hub. Plug your MIDI interface directly from the computer to the synthesizer. Why? Some external USB hubs fail when multiple USB devices are attached because there is not enough power to share. Small power sags will suddenly cause one or ALL of the attached USB devices connected to the hub to fail, often accompanied with a "disconnect" signal
These MIDI interfaces have been tested and will work with large SysEx Dumps:
✓ ESI Midimate II ✓ MOTU 823 mk3 ✓ RME FireFace UC 2X2
✓ Focusrite Scarlett 2i4 2nd Gen ✓ M-Audio Profire 2626 ✓ ESI Midimate eX
✓ Focusrite Scarlett 4i4 2nd Gen ✓ Miditech MIDIface II Thru ✓ Yamaha UX 16 USB/MIDI
✓ Focusrite Scarlett 6i6 3rd Gen ✓ Tie Studio MIDI 1i1o ✓ Miditech MIDIface 4x4
✓ iConnectivity mio 1x1 ✓ iConnectivity mioXC 1x1
These MIDI interfaces are shit and do not work with large SysEx Dumps(some might w/special driver):
✗ AVID/M-Audio Fast Track Pro ✗ M-Audio MIDISport UNO ✗ M-Audio MIDISport 1x1
✗ M-Audio MIDISport 2X2 ✗ M-Audio Uno ✗ Lekato MIDI USB
✗ DigitalLife MIDI-C01 ✗ Fore MIDI Interface ✗ Hosa USM-422 MIDI
✗ Hosongnic, Urweonu, HiFangeow, etc...
* * * SUPER JX FAQ * * *
Note:Most of the procedures and commands shown on this page are specific to JX‑10 and MKS‑70 synthesizers with Roland factory stock ROM IC's installed. If you are seeking answers for a JX‑10 or MKS‑70 with ROM IC versions higher than v2.30 (JX‑10) or v1.08 (MKS‑70), please check the Vecoven Project Page for more details. There are manuals and FAQ's online at that site which contain all the answers you will need
QUESTION
ANSWER
Where Can I Find Owners Manuals For The JX‑10 And MKS‑70 Synthesizers?
FREE Owner's Manuals for almost every synthesizer and effects device can be fount at MidiManuals.com;
X-10, MKS-70 and PG-800 Service Manuals w/schematics may be downloaded FREE at synfo.nl
These are the highest quality on the Internet. Gigantic collection of many synthesizers here;
The Complete JX-10 Service Manual (Note: Most online versions are missing pages 5, 6, 9 & 10... but not this one) Patience when downloading... this file is gigantic!
The Fluorescent Indicator Panel (FIP) On My JX‑10 / MKS‑70 Just Bit The Dust. What Now?
The FIP driver coil display is a common point of failure with JX‑10 and MKS‑70 synths. The cause is a manufacturing defect which has been traced to the Sumida Corporation, the only supplier of this coil (JX‑10 P/N: 12449251, MKS‑70 P/N: 12449283)
Unfortunately, sources for replacement coils are expensive and sometimes difficult to find. A supplier on eBay has some redesigned replacements which sell for $75 USD. Another hope is to find an old coil from a cannibalized Roland product which uses the same part number. The JX‑10, JX‑8P, GM‑70, GR‑1, DDR‑30, S‑50 and S‑550 synths/samplers use the same part number. However, be aware that these coils may also be defective. There seems to be no rhyme or reason as to when or if a coil will fail. Click on the image for a reference photo showing coil part numbers for different Roland gear
Note: The image on the right shows the coil on a GR‑1 Panel Board Assembly. The coil for a JX‑10 and an MKS‑70 is located on the Display Board but has a different silkscreen designation of T1
Another option is an exciting new development for a modern replacement display created by Guy Wilkinson. A Noritake VFD module can be retrofitted into the existing case of a JX‑10 or MKS‑70. It makes no difference which ROM IC version you have either. It will work with a factory stock system or one with a new Vecoven upgrade. The fonts are super huge, easy to read and it displays a lot more info than the old and boring factory installed display. Another cool feature is that it completely bypasses the old FIP driver coil circuit so there's no need to worry about that time‑bomb anymore. This new display can be purchased pre‑assembled or as a DIY kit. I have installed this display kit in my JX‑10 and it is an incredible enhancement. Highly recommended!!! Guy has an in‑depth website with all the details at supersynthprojects.com
(Noritake VFD)
Here are two videos which describe this new add‑on in more detail
How Difficult Is It To Repair Or Replace A Defective Alpha‑Dial Rotary Encoder On The Super JX?
Guy Wilkinson to the rescue again! Another breakthrough in the Super JX DIY world. A replacement encoder for under $2. Super simple to install and IMO, it works better than the original! Everything you need to know is at supersynthprojects.com
I've designed some replacement encoder boards which are "almost" a drop‑in solution. A new PCB uses the existing connector and wiring harness on the Super JX‑10 or MKS‑70 (the difference between these two synth boards is the encoder shaft length: 15mm vs. 25mm). Simply solder the new $2 Bourns encoder and the old encoder wire harness onto this new PCB and pop it in place. Just follow the same instructions found at the supersynthprojects.com website shown above
I've set the price of this PCB with zero markup costs. The PCB ships anywhere in the USA for FREE. Shipping is also FREE outside of the USA but some countries may add some hefty customs and handling fees onto the final price. My investment costs in producing this PCB is zero... only my design time. You can order these PCB's from OSHPark at a minimal cost and the installation instructions are printed on the PCB. Because these PCB's are so tiny, OSHPark will only sell a minimum of three PCB's at a time. The price works out to about $1 per PCB. Still a bargain, especially if you own more than one Super JX
Note: The encoder for the MKS-70 uses a different part number than the JX-10
The Cartridge Doesn't Store Data Or Sometimes The Data Appears To Be Corrupt. What's Wrong?
One major flaw with the JX‑10 is the flimsy and ill‑positioned ribbon cable connecting the cartridge port to the Assigner Board. After opening and closing the top case on the synth a few times, the ribbon cable can easily catch in between the hinges and get damaged. Also, the bend radius is very narrow. This particular type of ribbon cable is susceptible to trace failures as well. Over time, the bonding comes loose
Guy Wilkinson has created a clever DIY solution consisting of two add‑on circuit boards and some connectors which effectively replace the troublesome ribbon cable assembly. You simply source a couple of inexpensive parts on your own (IDC ribbon cable, two box headers and two ribbon cable sockets) then solder the circuit boards in place. I was able to easily source all the extra components. Guy also sells a complete kit with all the extra cables and parts and he tests it for continuity. This inexpensive DIY Kit is very easy to install. Afterwards, opening and closing the top case on a JX‑10 is no longer an event where holding your breath is a requirement
In a related topic about cartridge adapter PCB's, an online visitor was curious about replacing his MKS‑70 cartridge adapter and PCB. He bought a used MKS‑70 and unfortunately, the cartridge housing assembly and PCB were missing. Total bummer! In keeping with Roland's quirkiness of using different parts on similar synths, MKS‑70 and JX‑10 cartridge assembly PCB's are NOT interchangeable
The main problem with the PCB is that damn diagonal cut‑out on the MKS‑70 board is needed for it to fit snugly inside the case. Even if you were able to cut out that diagonal section from a JX‑10 PCB, the upper black plastic cartridge adapter with gold plated pins is soldered onto the PCB and is off‑center from an MKS‑70 PCB. It won't screw back into proper alignment
If your internal cartridge adapter is broken or missing, some good news here is the new Vecoven SuperJX-Flash Board is a great alternate solution. With 16 or 32 cartridge banks available at the press of a button, those expensive M‑64C cartridges won't be missed at all
MKS‑70 / JX‑10 Cartridge Adapter Assemblies (click for larger image)
Is There Any Way To Improve Sound Quality On The MKS‑70?
Absolutely! Plasma Music Limited offers a board called the Nebula which is a revised, up-to-date MIDI circuit and… balanced outputs!!! This is one amazing upgrade for an already stellar sounding classic analog synth. The big advantage of running balanced signals from your sources to your mixing desk or DAW audio interface is an increased immunity to noise. The Nebula is very simple to install and all of the components are pre‑soldered onto the PCB
Is There Any Way To Improve Aftertouch On The JX‑10?
Another boon for the JX-10 crowd. Plasma Music Limited has designed a Replacement Aftertouch Sensor. The JX-10 just got bumped up to a higher level for professional musicians! The info about how this new sensor works is a very interesting read
What's The Best Wiring Method When Performing The Vecoven v4.x PWM Upgrade?
Guy Wilkinson is great at designing innovative add‑ons for the Super JX and also provides some useful documentation as well for those wishing to perform the new Vecoven PWM upgrade. Be sure to visit his website with tips for a quality and successful upgrade. A recent addition is the PDF document titled, 'PWM Wiring IDC Method' with a visual layout when using IDC ribbon cable connectors. I highly recommend this method because it separates the new PWM circuit boards from the Assigner/Module Boards and helps to reduce any electrical interference
How Do I Restore The Factory Preset Patches And Tones Into The Internal Memory Of The Super JX?
[ WARNING!!! Everything in the internal Super JX memory will be erased! ]
MKS‑70
1) Connect MIDI Out and MIDI In cables between the Super JX and the computer
2) Set the Protect Switch on the MKS‑70 to the OFF position
3) Run one of the generic SysEx loaders for Mac or PC (found on the UTILITIES page at this website)
4) Load the factory presets file;
JX10BNK0-A.SYX(this file is available on the PATCHES page - See JX10_MKS70_Collection‑A.zip)
5) Follow the instructions for the SysEx loader program you are using and send the JX10BNK0‑A.SYX file to the MKS‑70
6) Once the load process begins, the screen on the MKS‑70 will read 'MIDI BULK LOAD PATCH **'
7) Factory presets will be be restored after the display cycles through Patches A1‑H8 and Tones 0‑50
Note: You may need to set the transfer speed within your generic SysEx loader to a slower rate depending on your computer.
Newer computers will send the SysEx data too fast and the MKS‑70 MIDI buffer is unable to handle the speed
JX-10
No matter how hard you try, you will never be able to restore Patches on a factory stock JX‑10 using a generic SysEx utility. The SysEx functions of the JX‑10 are crippled and do not work properly. Believe it or not, that's the way Roland designed it. You will need to use a special utility program such as CPJXWIN (Windows PC) or GenPatch (Atari ST) and have an M‑64C data cartridge plugged into the JX‑10 at the same time*. If you decide to use CPJXWIN or GenPatch, you may need to set the transfer speed within your generic SysEx loader to a slower rate depending on your computer. Newer computers will send the SysEx data too fast and the JX‑10 MIDI buffer is unable to handle the speed. Your other option is to replace the factory ROM IC's with the newer Vecoven ROM IC Upgrade which solves the SysEx problems
* You must have an M‑64C Cartridge plugged into the JX‑10 when using CPJXWIN or GenPatch
Note: An alternative way is to copy all Patches/Tones from an M‑64C cartridge if the factory presets have already been pre‑loaded onto the M‑64C cartridge. There is no other way to load factory preset Patches/Tones on a factory stock Super JX and there is no 'Power On Factory Reset' option
How Do I Save All Of My Patches And Tones Currently Inside The Super JX To A Computer Or Sequencer?
MKS‑70
1) Connect MIDI Out and MIDI In cables between the MKS‑70 and the computer
2) Run one of the SysEx utilities for Mac or PC and set it to 'Receive SysEx' (found on the UTILITIES page at this website)
3) On the MKS‑70, push the MIDI button then push the WRITE button. The display responds with 'WRITE MIDI'
4) Rotate the Alpha-Dial until the display responds with'MIDI BULK DUMP'
5) Push the ENTER button
6) All Patches are sent to the utility program on your computer. Save the file with a *.SYX extension
JX-10
No matter how hard you try, you will never be able to save Patches on a factory stock JX‑10 using a generic SysEx utility. The SysEx functions of the JX‑10 are crippled and do not work properly. Believe it or not, that's the way Roland designed it. You will need to use a special utility program such as CPJXWIN (Windows PC) or GenPatch (Atari ST) and have an M‑64C data cartridge plugged into the JX‑10 at the same time*. If you decide to use CPJXWIN or GenPatch, you may need to set the transfer speed within these custom SysEx loader programs to a slower rate depending on your computer. Newer computers will send the SysEx data too fast and the JX‑10 MIDI buffer is unable to handle the speed. Your other option is to replace the factory ROM IC's with the newer Vecoven ROM IC Upgrade which solves the SysEx problems. This is the BEST option and is well worth the minimal investment
* You must have an M‑64C Cartridge plugged into the JX‑10 when using CPJXWIN or GenPatch
How Do I Copy Patches & Tones From The M‑64C Cartridge Into The Internal Memory Of The Super JX?
To load Patches & Tones from the M-64C cartridge into the Super JX internal memory:
[ WARNING!!! Everything in the internal Super JX memory will be erased! ]
JX-10
1) Set the Protect Switch on the M-64C cartridge to the ON position
2) Set the Protect Switch on the JX-10 to the OFF position
3) While holding the WRITE button down, push the CART▽INT button
4) The display responds with: 'COPY CARTRIDGE TO INTERNALMEMORY'
5) Push the ENTER button and the display responds with 'LOAD COMPLETE'
6) Return the Protect Switch on the Super JX to the ON position
MKS-70
1) Set the Protect Switch on the M-64C cartridge to the ON position
2) Set the Protect Switch on the MKS-70 to the OFF position
3) Push the WRITE button (The display responds with: 'WRITE MODE')
4) Rotate the Alpha-Dial until the display responds with:
'COPY CARTRIDGE TO INTERNALMEMORY'
5) Push the ENTER button and the display responds with 'LOAD COMPLETE'
6) Return the Protect Switch on the Super JX to the ON position
How Do I Copy Patches & Tones From The Internal Memory
Of The Super JX Onto The M‑64C Cartridge?
To save Patches & Tones from the Super JX internal memory onto the M-64C cartridge:
[ WARNING!!! Everything in the M-64C cartridge memory will be erased! ]
JX-10
1) Set the Protect Switch on the M-64C cartridge to the OFF position
2) Set the Protect Switch on the JX-10 to the ON position
3) While holding the WRITE button down, push the INT▽CART button
4) The display responds with: 'COPY INTERNALMEMORY TO CARTRIDGE'
5) Push the ENTER button and the display responds with 'SAVE COMPLETE'
6) Return the Protect Switch on the M-64C cartridge to the ON position
MKS-70
1) Set the Protect Switch on the M-64C cartridge to the OFF position
2) Set the Protect Switch on the MKS-70 to the ON position
3) Push the WRITE button. The display responds with: 'WRITE MODE'
4) Rotate the Alpha-Dial until the display responds with:
'COPY INTERNALMEMORY TO CARTRIDGE'
5) Push the ENTER button and the display responds with 'SAVE COMPLETE'
6) Return the Protect Switch on the M-64C cartridge to the ON position
I Can't Get The Super JX To Communicate With
My Computer When Using A Librarian Or SysEx Program. What Should I Check?
The most common communication errors are with System Exclusive so... let's start with that one;
1) Is System Exclusive turned ON and MIDI Channel set to 1?
Use the front panel buttons on the Super JX and make sure these settings match up;
MKS-70
[ 1 ] CONTROL CHANNEL
[ 1 ] CHANNEL A
[ 1 ] CHANNEL B
[ ON ] PATCH PROG CHANGE
[ ON ] SYSTEM EXCLUSIVE
[ ON ] A PROG CHANGE
[ ON ] B PROG CHANGE
JX-10(Requires a special program such as CPJXWIN (Windows), GENPATCH (Atari) or ROM IC equal to or greater than v2.30SE)
[ 1 ] CONTROL CHANNEL
[ 1 ] UPPER MIDI CHANNEL
[ 1 ] LOWER MIDI CHANNEL
[ ON ] PATCH PROG CHANGE
[ ON ] SYSTEM EXCLUSIVE
[ ON ] UPPER PROG CHANGE
[ ON ] LOWER PROG CHANGE
Note: To save these MIDI settings in memory for future use; PRESS THE 'MIDI' BUTTON
PRESS THE 'WRITE' BUTTON
PRESS THE 'ENTER' BUTTON
2) Is the computer Sound Card, MIDI Controller, SysEx Librarian, etc... set to MIDI Channel 1?
3) Is the computer Sound Card, MIDI Controller, SysEx Librarian, etc... sending MIDI data to the Super JX?
4) Do you have an M-64C cartridge plugged into the Super JX-10?
You MUST have an M-64C cartridge plugged into the JX-10 if your ROM IC is v1.72 through v2.30
5) Make sure the patch librarian and SysEx program can send and receive SysEx data to and from the Super JX
Set the 'PROTECT' switch on the Super JX to the 'OFF' position Set the 'PROTECT' switch on the M-64C cartridge to the 'OFF' position Note that there are two switches to check. One switch is on the M-64C cartridge and the other switch is on the Super JX
The 'Protect' switch for a JX-10 is on the back panel, next to the PG-800 Programmer port
The 'Protect' switch for an MKS-70 is on the front panel, next to the PG-800 Programmer port
6) Do you have two MIDI cables connected? Two are required because SysEx uses both MIDI IN & MIDI OUT
7) The MIDI Send and Receive settings on your computer might be too fast for the Super JX MIDI buffer to handle. The Super JX synth was designed back in Medieval times when the processor speed of a home computer was only 20MHz... much slower than the models of today at 4GHz. Try setting the MIDI transmit speed in your computer's SysEx program to a smaller value. Recommended values for Snoize, Bome and MIDI‑OX are 390ms
8) Is the MIDI interface connected to a USB hub? USB hubs are notorious for transfer glitches. Plug straight into the computer
9) Another thing to check is the MIDI INTERFACE connected to your computer. Some inexpensive MIDI interfaces which look similar to this one are unable to properly regulate the buffering of MIDI data. Some of these inexpensive MIDI interfaces will work fine with simple messages such as CC, Note On, Note Off, etc... However, when you try to send SysEx messages which are much longer, the SysEx data cuts off after only sending a few bytes. Investing in a higher quality MIDI interface may solve Load/Save errors and other communication problems
How Do I Copy Tones From A JX‑8P (M‑16C Cartridge) To An MKS‑70 or JX‑10?
1) Create an internal patch that only uses Tones from 1 - 32
2) Press the 'SHIFT' button
3) Press the 'CARTRIDGE' button
4) Select a Tone from Cartridge 1 - 32
5) Press the 'ENTER' button
Mr. Richard Feder of Fort Lee, New Jersey asks;
'How Do I Load Individual JX‑8P Tones From A Computer Into An MKS‑70 or JX‑10? Is it Easy? Is It Difficult? What MIDI Settings Do I Need To Change? Does It Work On A JX‑10?"
"Dear Mr. Feder,
You sure do ask a lot of questions for a guy from New Jersey!"
First off, it's worth noting that Dave Scoging spent tons of time converting 300+ JX‑8P Tones into JX‑10 and MKS‑70 format and are courtesy of the Fred Vecoven Super JX ROM Project. They are on the PATCHES page for downloading.
Before loading or saving individual Tones to or from the computer, make sure these MIDI settings are correct on your synth;
MKS-70
[ 1 ] CONTROL CHANNEL
[ 1 ] CHANNEL A
[ 1 ] CHANNEL B
[ ON ] PATCH PROG CHANGE
[ ON ] SYSTEM EXCLUSIVE
[ ON ] A PROG CHANGE
[ ON ] B PROG CHANGE
JX-10(Requires the Vecoven ROM IC v3.00 or greater)
My rule about SysEx is, 'When dealing with SysEx communication errors... set all parameters to ON'
Using MKS-70 w/ROM IC v1.03 and up:
Load an individual JX-8P .syx Tone file from the computer into a generic SysEx file librarian program like Snoize (Mac) or Bome (Windows).
On the MKS-70, choose a Patch (C-4 for example) then send the SysEx from the generic SysEx file librarian program to the MKS‑70. It will load automatically into the Tone A slot. The flashing period next to the Tone A number indicates a new Tone was loaded into that slot.
Using JX-10 or MKS-70 w/ROM IC v3.00 and greater:
Same as above
Using JX-10 w/ROM IC v1.72 through v2.30:
Not Possible. System Exclusive for loading or saving individual Tones is not functional on a factory stock JX‑10
Using JX-10 w/ROM IC v2.30SE:
Not Possible (unless the JX-8P Tones are first converted into a special format by a software genius)
How Do I Change The Internal Back‑Up Battery?
I recommend that you take your synthesizer to a Roland Authorized Service Center because installing a new battery is a tedious task. The battery is soldered onto the Assigner Board. But...... if you're a real sicko like me and insist on saving pennies because you have that foolish "I can do that myself" attitude...... then...... detailed instructions are available. A big advantage of taking it to a Roland Authorized Service Center is that if they accidentally "pop" an IC because of static discharge, the cost is on them
My Super JX Seems To Be Experiencing Some Noise, Buzzing And 60 Cycle Hum? Is There A Way To Eliminate This Noise?
One of the contributors (scottrod) on an online forum at gearsz.com offers this fix;
'Got an MKS-70 with the same problem, serious 60‑cycle hum artifacts on all outputs. Raising or lowering volume pot doesn't change hum level. Recapped power supply, no change. Turned out to be the wire routing inside the unit. This one was untouched inside, purchased from original owner. All the low power DC lines (±15, +5, grounds) coming from the power supply unit going to the assigner and module boards were routed right next to the main power transformer. Rerouted the lines to keep everything as far away from the transformer as possible; all hum gone, super clean outputs now.'
Many Thanks to scottrod who has put together this intricate and amazing photo DIY guide for eliminating the 60‑cycle hum problem. The amazing part is that you don't need to cut any wires. My favorite kind of mod! This DIY guide could also be very useful for JX‑10 owners
Also, many thanks go out to Guy Wilkinson at Super Synth Projects who has compiled a detailed and informative DIY webpage for eliminating noise on the MKS‑70. Once again... no wires to cut making this an efficient, cost effective upgrade
Having trouble with Split Keyboards on the MKS‑70?
The MKS-70 has three MIDI channels, one each for Tone A and Tone B blocks, and one for the control channel. If the control channel is the same as one of the Tone A or Tone B blocks, some single channel controllers will only play one of the blocks. Try changing Tone A and Tone B blocks to a different channel.
Note: The control channel setting for the MKS-70 is MIDI parameter [ 12 - CONTROL CHANNEL ]. This is also the MIDI channel which is normally set to MIDI channel #1. It is recommended that the Tone A and Tone B MIDI channels be changed instead. These are MIDI parameters [ 21 - CHANNEL A ] and [ 31 - CHANNEL B ] respectively.
Why Does My MKS‑70 Only Play One Tone Across Half The Keyboard And Then Nothing Or Just Play One Tone Or Both Tones All The Way Across The Keyboard?
Sometimes Patches that were created on the JX‑10 do not set the split points properly when loaded into an MKS‑70. Going into the Patch menu and re‑setting the split points and then saving the Patch should fix this problem
The Aftertouch On My JX‑10 Keyboard Doesn't Seem To Be Very Responsive. Is there A Way To Fix It?
The latest and greatest 21st century solution for improving aftertouch is a DIY kit developed by Plasma Music Limited. This replacement kit includes an FSR interface PCB and FSR sensor strip. I have installed this on my JX‑10 and am in total awe at the responsiveness this thing can deliver. There's no comparison between this new one and a factory AT Strip. It blows the old one out of the water and I highly recommend it
On the original factory installed aftertouch strip, oxidation builds up over time on conductive plates which control the aftertouch signals. The SuperSynthProjects website hase some very useful tips and tricks for bringing a factory installed AT Strip back to life
Is There A Way To Improve The Sound Output On A Super JX?
Absolutely! The PARALLEL OUT jacks are not explained very well in the Super JX Owner's Manual. One website visitor has passed along an excellent overview of how to use these special audio jacks to create some monster sounds:
==================
Binaural Audio Effect
==================
"Connecting just the outer two jacks of the PARALLEL OUTPUT does NOT create optimum results. In that case, both layers stay in the middle of the stereo field even when they are panned apart at the destination. Yes, if chorus is enabled, it will be stereo. However, for a 'Binaural Audio' effect, each layer is *exclusive* to each side of the image so you need to have plugs in all four jacks!
It's a pretty ingenious setup which Roland engineered in the JX‑10 and MKS‑70; they are auto‑sensing jacks that know when something is plugged into them, and the stereo image changes accordingly. If you've only ever used the outside pair, do yourself a favor and plug some dummy plugs into the inner two jacks and call up a big dual mode pad. Biggest, widest analog pads you'll ever hear. When you switch back to single ('WHOLE') patches, you have to either unplug the inner two cables, or mute them and change your pan settings on your mixer. A minor pain, but I tend to always use the JX‑10 and MKS‑70 in DUAL MODE, typically for those big pads."
It's important to note that the "H-M-L LEVEL" slider switch will only affect audio from the TOTAL MIX OUTPUT jack and has no control over any of the PARALLEL OUTPUT jacks
One Or More Of The Keys On My JX-10 Won't Play Sound Or Will Only Play Sound Some Of The Time. What Should I Check?
As usual, Guy Wilkinson has some of the best advice around. This very detailed guide for repairing keyboard contacts will get your JX‑10 back to normal. The repair info here can also be applied to other Roland keyboards such as the W‑30, S‑50, D‑50, Alpha Juno‑2, etc... since they use the same style membrane
The Buttons On My Super JX Are Working Intermittently. Is There A Way To Fix It?
30 Years later, the buttons (tact switches) are starting to fail. The best solution is to replace all of them at the same time because if you only replace a few, others are bound to fail soon after. eBay and other vendors sell complete sets of tact switches and these range anywhere up to $92. Ouch! You can save a lot of money buying them instead from an electronics supplier such as mouser.com
JX‑10
There are two types of tact switches to choose from. I prefer a harder press Operating Force of 2.6 Newton. A total of 53 switches are needed (Do yourself a favor and buy a couple of spares because... shit happens)
1)Brand Name: ALPS
Manufacturer P/N: SKHCBFA010
Mouser P/N: 688-SKHCBFA010
Operating Force: 1.3 Newton* Operating Life: 1,000,000 cycles
Size: 4.3mm (H) x 12mm (W) x 12mm (D)
For unknown reasons, the ALPS price has tripled As of
, OMRON P/N: B3F-4000 is the best value
2)Brand Name: ALPS
Manufacturer P/N: SKHCBHA010
Mouser P/N: 688-SKHCBHA010
Operating Force: 2.6 Newton
Operating Life: 500,000 cycles
Size: 4.3mm (H) x 12mm (W) x 12mm (D)
For unknown reasons, the ALPS price has tripled As of
, OMRON P/N: B3F-4005 is the best value
*Original JX-10 factory tact switches had a 1.3 Newton Operating Force
Roland P/N: 13129704 - ALPS P/N: SKHCAB131A
This same switch is also used on the Alpha Juno‑1, Alpha Juno‑2, HS‑1 and HS‑80 synths
OMRON brand tact switches P/N: B3F‑4000 (1.3 Newton) and P/N: B3F‑4005 (2.6 Newton) will also work
MKS‑70 (Note: There is a very detailed webpage complete with images and step‑by‑step instructions for these tact switch replacements at SuperSynthProjects.com)
There are two types of tact switches to choose from. I prefer a harder press Operating Force of 2.6 Newton. A total of 30 switches are needed (Do yourself a favor and buy a couple of spares because... shit happens)
1)Brand Name: ALPS
Manufacturer P/N: SKHHAPA010
Mouser P/N: 688-SKHHAP
Operating Force: 1.6 Newton
Operating Life: 500,000 cycles
Size: 9.5mm (H) x 6mm (W) x 6mm (D)
**Original MKS-70 factory tact switches had a 2.6 Newton Operating Force
(Roland P/N: 13159154 - ALPS P/N: SKHHBS)
This same switch is also used on the MKS-50 synth
The Operating Life for all of these switches is realistically 10 years until stress and/or oxidation starts to set in and they become intermittent. Removing old tact switches from the PCB is a matter of personal preference. The method I prefer is by using a small sharp pair of diagonal flush wire cutters and cut all four leads off from the top side of the PCB. Take extra care not to wedge the wire cutters in‑between the base of the tact switch and the PCB when cutting the leads.
This places excess force on the eyelet trace on the underside of the PCB causing possible damage. Use a solder sucker, a fine tipped soldering iron or a stainless steel hollow desoldering needle and remove the leftover pins from the PCB holes. Remove any excess solder remaining in the holes. The eyelet traces on the brittle 30‑year old PCB are very fragile. Take extra care not to lift them off the surface of the PCB while desoldering. Using too much heat or keeping the soldering iron too long in one spot usually leads to this type of problem
While we're on the subject of replacing buttons... you might want to consider replacing those crumbling foam inserts which separate the buttons from the tact switches. These cushions start to break apart after years of use. A visitor to this website and Super JX owner suggested using a sheet of Neoprene. I bought a sheet and it works incredibly well. In fact, I think it works better than the original cushions. The buttons stand up straight, they are in perfect alignment with the sides and they're uniformly flat along the tops. It makes the button presses a little more rigid which is my preference
I recommend using Neoprene sheets which are 1/16' thick, the same thickness as the original cushions. As of April 2024, you can find a roll of 1/16" x 12" x 12" Neoprene from USA vendor rubbersheetwarehouse for $12 and FREE shipping. Heck of a bargain! I've found the easiest way to cut out the round holes is by using miniature scissors found on most Swiss Army knives.
(Crumbling foam insert riddled with holes)
Over the years, the button cushions on my JX‑10 crumbled into dust and I was unable to replace them easily since I had no sizes for reference. I purchased a 2nd JX‑10 later on and made exact measurements of the cushions which were partially intact. If you are in a similar situation, here are some templates and instructions for making your own
Note: The button cushion shown to the right sits underneath the numeric keypad. This one is in an advanced state of deterioration and the '+' patterns have been worn away after decades of use. The only holes you need to cut out are the round ones. There are a total of three button cushions to replace (65mm x 80mm, 250mm x 55mm and 255mm x 55mm)
What Are My Options For Replacing The Sliders On A JX‑10?
Most scans of the JX‑10 Service Manual found online have omitted the schematics and board layouts for the Volume Board. This PCB contains the six sliders in question. I recently found a complete version of the JX‑10 Service Manual and the download link is near the top of this page
After a visual inspection and removing the sliders from the Volume board, here's some info I was able to find:
There are six slider pots labeled VR1, VR2, VR3, VR4, S1 and S2. Four are potentiometers and two act as switches. Compared to normal slider pots I've seen available for purchase, the JX‑10's are unusual because they have a quad set of pins on each side which makes them impossible to source. The only source I know of is buying a used Volume Board on eBay. Even then, the sliders on it would probably be just as crappy as the ones you are trying to replace. Because these are so difficult to find and replace, most JX‑10 owners carefully disassemble the original slider pots, clean them with DeoxIT Fader Lube and reassemble. Special care needs to be taken when cleaning since these are vintage sliders. It's very easy to accidentally remove the carbon layers inside which will render them useless
Each slider shares these identical characteristics:
Dimensions = 45mm (L) x 8mm (W) x 6mm (H)
Pins = 8 (Actually, 10 but two are used for stabilizing the outer case and shielding) Lever Travel = 30mm
Insulated Lever = 15mm from the top of the outer case to the tip of the lever
Pin Spacing Template = See the 9‑page JX‑10 Slider FAQ
And, here are the individual specs:
Function Board Component Case Markings Notes
------------- --------------- ------------- --------------------------------------------
MASTER VOLUME VR1 M 50KΩD 62 D 50K Ω Slide Potentiometer: Logarithmic Taper
C1 VR2 10KΩB 62 1E 10K Ω Slide Potentiometer: Linear Taper
C2 VR3 10KΩB 62 1E 10K Ω Slide Potentiometer: Linear Taper
AFTERTOUCH VR4 10KΩB 62 1E 10K Ω Slide Potentiometer: Linear Taper
BEND RANGE S1 M 63M Ω Slide Switch: Has 2 detents + 4 settings
VOICE MEMORY S2 M 63M Ω Slide Switch: Has 2 detents + 4 settings
If you are serious about replacing any of these sliders, I've put together a very detailed FAQ. This lengthy document contains pin resistance measurements while removed from the Volume Board, dimensions, rebuild info... everything except where to buy replacements
JX‑10 Volume Board Front And Back w/Notations - Click For Larger Image
My Super JX Won't Power On Or It Acts Strange After Warming Up. What Should I Check?
Guy Wilkinson has done it again! A completely redesigned power supply unit for the JX‑10 and MKS‑70 is now available as a DIY project or as a pre‑built option. This innovative design using a single PCB replaces the power supply board AND the transformer! It also eliminates the common issue of old leaking electrolytic capacitors and dry joint degradation +plus+ it runs cool and automatically uses any mains voltage from 110VAC to 240VAC. The newest version will also work with a JX‑8P
This alternative to the clunky design from the 1980's eliminates transformer hum and uses modern day components to replace older technology. A combination of through‑hole and large SMD component sizes (2320, 1210 & 0805) with very large PCB pads makes soldering a breeze. This was the easiest SMD project I've ever worked on and I think a beginner would be able to easily tackle this one as their first SMD project. After getting this expertly made PCB, I've been able to easily source all of my components from Mouser, eBay and Tayda. Extensive bench test results, Bill Of Materials and build documentation are at https://supersynthprojects.com/replacement-jx10-mks70-power-supply/
Hard to believe but... Molex still manufactures these hard to find JX‑10 and MKS‑70 cable assembly connectors for as low as 30¢ each (shown below). Here is an image after I soldered them onto this new PCB. It was very satisfying to hear the "click!" sound when the cables snapped in place. The 30+ year‑old Roland connectors are worn out and don't have any more spring to them. You can find these at mouser.com by doing a search for "Molex 5267 538-22-03"
Guy Wilkinson has compiled an excellent comprehensive tutorial for repairing and/or rebuilding an MKS‑70 or JX‑10 power supply. Visit his supersynthprojects.com webpage for detailed step‑by‑step instructions and a spreadsheet with part numbers. His power supply rebuild instructions absolutely put mine to shame ;^)
* I'm keeping my info available temporarily in the event someone has already started a PSU rebuild which references this page
Left: Q1 / Q4 - Right: Q5
One of the most common failure points for the Super JX and other Roland synths is the Power Supply Unit (PSU). After 30+ years, the sub‑par solder used by Roland has a tendency to break down and cause hairline fractures. This occurs at a higher rate for components which generate a lot of heat like the Bridge Rectifiers (D4 & D5), Power Transistors (Q1, Q4 & Q5), and the three large Electrolytic Capacitors (C11, C12 & C13). If you have problems with no power, intermittent power or the synth acts weird after warming up, chances are good that a hairline crack is the cause. These cracks in the solder are nearly impossible to see. Use a magnifying glass to inspect the bottom of the Power Supply Unit and reflow NEW solder on any suspect areas
One problem area on the PSU are the three Power Transistors (Q1, Q4 & Q5). These components generate a lot of heat which is why they are attached to a giant aluminum heat sink. After hundreds of heat cycles being powered on and off and also from case movement, these components will sometimes fail or cause hairline solder fractures. Toshiba P/N: 2SB1015 (PNP) and 2SD1406 (NPN) can sill be purchased from various vendors at eBay
Guy Wilkinson shared an excellent tip for preventing future problems with these Power Transistors. Don't cut the pins flush and bend the end of each lead at a right angle to strengthen the joint. "I found the solder pads for the transistors way too weak for the PSU in the MKS70 - because the casing/bottom lid flexes slightly when you move it thus putting strain on the joints. So I boosted the pads before fitting new transistors. This way is very secure." ‑‑supersynthprojects.com
Another issue with strange behavior can be traced to a defective electrolytic capacitor. After 30+ years and a lot of power surges, some electrolytic capacitors have a tendency to bulge and leak. For the Super JX, it's a good practice to recap the PSU. It's a fairly straight forward job to replace all ten electrolytic capacitors and the cost is under $13 (USD). Service Manuals for the JX‑10 and MKS‑70 show identical PSU part numbers. In fact, you will notice on the MKS‑70 PSU that "JX‑10 / MKS‑70" is silkscreened in the lower left corner
(Recapping The PSU - Ten Electrolytic Capacitors)
However, there are some slight differences. For example, when compared to the JX‑10, the MKS‑70 PSU is missing the large black Line Filter (L1) and has two additional daughter‑boards for those components. One is the EMI Board and is soldered onto the lower left corner of the PSU. The other is the Filter Board which is mounted towards the back of the case. This board contains the missing Line Filter (L1). The important thing to note is that all of the Electrolytic Capacitors and Power Transistors are identical on the PSU for both Super JX models
Three of the caps are gigantic and the other seven are normal sized. The LEAD SPACING and the DIAMETER sizes are not critical for the smaller caps but these need to be exact for the three large caps. Otherwise, C11, C12 and C13 won't fit onto the PSU. The three large caps are somewhat difficult to remove because they are glued to the PCB so use an X-Acto knife or a razor blade to carefully cut the glue away from the base of the PSU. The PSU is 30+ years old and the solder traces have a tendency to separate from the surface. Use caution by choosing a lower heat setting than normal for the soldering iron and don't keep it on the PSU for too long. Feel free to use different manufacturers part numbers*, but make sure the VOLTAGE is equal to or greater than the original specs. Keep in mind that increasing the voltage rating on any of the three large caps might increase the diameter size. (Note: Some of the caps shown below have a slightly higher voltage rating than the original specs. The original voltage specs are shown in red)
PART NUMBERS AND SPECS FOR RECAPPING (mouser.com)
QUAN VALUE VOLTAGE DIAM SPACING TYPE/TERMINATION PCB LOCATION PART NUMBER PRICE TOTAL
---- ------ ------- ----- ------- ------------------- ------------ -------------- ----- -----
1 1uF 50V/50V 5mm 2mm Electrolytic/Radial C4 ULD1H010MDD1TD $0.16 $0.16
2 4.7uF 50V/35V 5mm 2mm Electrolytic/Radial C3 - C8 ECA-1HM4R7 $0.20 $0.40
1 10uF 50V/16V 5mm 2mm Electrolytic/Radial C1 ECA-1HM100 $0.20 $0.20
3 100uF 50V/16V 8mm 3.5mm Electrolytic/Radial C2 - C6 - C9 ECA-1HM101 $0.33 $0.99
2 4700uF 35V/35V 25mm 10mm Electrolytic/Snap In C12 - C13 LGU1V472MELA $3.19 $6.38
1 6800uF 35V/35V 25mm 10mm Electrolytic/Snap In C11 LGU1V682MELA $3.77 $3.77
---------------------------------------------------------------------------------------------------
$11.19
*When choosing new caps, do yourself a favor and select only quality brand name manufacturers such as Nichicon, WIMA and Panasonic. The cheapo brands from eBay and China will probably give you more problems down the road in less than 10 years time
Springs Used For JX-10 Sharp Keys And Natural Keys Are Different Lengths And Different Tensions
Over the decades, I've been using this method to easily identify different JX‑10 keyboard springs. Prior to removing the springs, use a black Sharpie and place a mark on all the springs used for black keys. This will speed up reassembly
What Are The Pin‑outs For A PG‑800 Cable And How Do I Build One?
The PG-800 cable is a 6-Pin straight through cable. Click here for a DIY on how to build one yourself
Where Can I Get MKS‑70 And JX‑10 Questions Answered?
On January 1, 2015 a new Facebook page for JX‑10 and MKS‑70 owners and developers was created;
What Are The Main Differences Between The JX‑10 And The MKS‑70?
Other than the keyboard, the architecture of these two synths is virtually identical. They both use similar Module and Assigner boards. The JX‑10 has inputs on the back for external devices like an EV‑5 expression pedal and a DP‑2 pedal which can double as a switch pedal (to step through Patches) or as a hold pedal to sustain notes. The JX‑10 also has a built‑in sequencer. A single sequence can be saved onto an M‑16C or M‑64C cartridge. The MKS‑70 has a full octave bend range while the JX‑10 can only bend notes up to a perfect fifth. The biggest difference is the lack of SysEx commands available for the JX‑10. A factory stock JX‑10 is a real outcast when trying to communicate with computers or other hardware. Thankfully, the Vecoven ROM IC upgrade has corrected this oversight and provides full SysEx communication for the JX‑10 plus a lot of other great enhancements
Factory Synth Keyboard SysEx Sequencer Bender Range Pedal Control C1/C2 Control------------- -------- ---------- --------- ------------ ------------- -------------
JX-10 YES LIMITED YES 2-3-4-7 YES YES
MKS-70 NO YES NO 2-3-4-7-12 MIDI ONLY NO
It's important to note that the "H-M-L LEVEL" slider switch will only affect audio from the TOTAL MIX OUTPUT jack
This switch has no control over any of the PARALLEL OUTPUT jacks
* * * SUPER JX ROMS & FIRMWARE * * *
Information about Super JX ROM's previously located at this spot has been moved to a separate webpage
It's important to note that the "H-M-L LEVEL" slider switch will only affect audio from the TOTAL MIX OUTPUT jack and has no control over any of the PARALLEL OUTPUT jacks
Is there any way to tell the exact date my JX‑10 or MKS‑70 was manufactured and the actual Production Number?
Yepperdoodle! Here are two charts you can use to cross reference your serial number with a "Born-On" date and the actual Production Number when it rolled off the assembly line. These charts will also work with other Roland synths, samplers and miscellaneous gadgets like Boss Pedals, MicroSeries Effects, Sequencers and MPU Cards. The dates only cover Roland gear manufactured from 1972 through 2010 because Roland decided to abandon their serial number/date scheme... just like they abandon all other types of support
8‑Foot Cable Available At sweetwater.com + Always FREE Shipping / NO Minimum!
Tired of always looking for that oddball 2-Prong AC power cable? I was... and I did something about it.
Here's a super simple mod that will let you use the more common 3‑Prong AC cable. The mod is so simple that all it needs is a picture to explain. It's easy as 'connect the dots'. If you buy the correct sized AC power adapter, it's a 1 for 1 swap, no case modification and no sheet metal to cut. There's even a pre‑drilled hole in the case for the ground wire. Just piggy‑back onto one of the screw holes used for the serial number plate. Easy!
In addition to always being able to find the right AC cable, this mod adds ground circuit protection. Why is that important? Just ask some JX‑10 and MKS‑70 owners who connected their synth to an ungrounded mixing board. The audio output transistors on their synths were toasted!!!
The image shows the DIY mod for an MKS‑70 but this will also work with a JX‑10, Alpha Juno‑1, Alpha Juno‑2, HS‑10 and HS‑80 and many Roland synths. If you are using a synth with something running on power other than 110/117V AC, please note... this mod has NOT been verified to work on a synth running 220V/240V. This DIY mod is only for those with electronics experience. The author accepts no liability if you damage your synth or kill yourself. Unplug the synth from the power outlet and when working with electricity, always keep one hand behind your back. It's the best way to stay alive
* These rocker switches are required if sometime in the future you plan to install a Wilkinson Power Supply Replacement (available from supersynthprojects.com). These rocker switches are required because they are able to handle a higher rated capacitive surge as compared to a standard rocker switch
** The original factory rocker switch has no actuator markings on the face like some of these replacements. The original switch has a red bar which appears on the lower side when the switch is turned on. It's a totally useless design because you can't even see the red bar unless your eyelevel is underneath the synth! Weird!! I've concluded that the power switch was installed upside‑down at the factory because when you view the label on the switch from inside the JX‑10 case, the lettering is upside‑down. Every JX‑10, U‑20 and Alpha Juno‑2 I've ever seen is the same way as shown here. Most likely, installing it upside‑down was a suggestion made by the same engineer who designed the original JX‑10 SysEx code ☺
The replacement switch most similar to the original is Mouser P/N: 633‑CWSA11AANS but it does not have the red bar. I've always hated the original switch because it was so difficult to see against the dark backplate. I opted to replace mine with P/N: 633‑CWSA11AAN1S because it has a better visibility. The price for P/N: 633‑CWSA11AAN1S as of August 2023 was $2.42 (USD). The original rocker switch (Roland P/N: 13149108) was also used on a zillion other Roland synths and devices some of which include the Alpha Juno‑1, Alpha Juno‑2, JX‑8P, Juno 60/106, U‑20, JV‑80, JD‑800, D‑10/20/50/70, MK‑80, and MPU‑101
I'm posting these two alternative switches from Tayda because of the low cost and high visibility of the red switch A‑5092. These are DPST switches, have the same power rating and will work equally well as the switches from Mouser. The price for these as of August 2023 was only 30¢. After evaluating all types, I prefer the higher quality switches from Mouser
If your old switch is experiencing problems, don't bother trying to repair it. Some of the parts inside are sealed in plastic and other parts are wired in place. Repairing it is a lost cause. This power switch works with the MKS‑70 and a wide selection of other Roland synths and samplers including the D‑110, D‑550, GM‑70, JV‑880, MKS‑20, MKS‑50, MKS‑80, MKS‑100, S‑220, S‑550 and U‑220. In the 1980's and 1990's, this power switch was also used with a variety of Sony/JVC/Panasonic TV's and component stereo devices. This power switch is quite robust and more expensive than most. Replacements can be found on eBay for less about $10 (USD). Do a keyword search for "ALPS SDGA3P"
Replacement Headphones Jack (Silkscreen location is JK2 on the Jack Board) [ JX-10 Only ]
CUI Devices P/N: SJ-63053B Yamaha: VE382300 Jalco: YKB21-5010
Note:This same P/N: is also used as the Headphones Jack for Roland Alpha Juno‑1, Alpha Juno‑2, D‑20, GR‑1, HS‑10, MKS‑50, MKS‑100, S‑10, S‑220 and U‑20
Replacement Fuse [ JX-10 & MKS-70 ]
The JX‑10 and MKS‑70 use different fuse values. For detailed replacement info, check the Roland Fuse Reference Page (117V SYSTEMS ONLY)
The PG‑800 programmer gives easy access to all of the editing features on the Super JX‑10 and MKS‑70. Most Super JX‑10 and MKS‑70 owners prefer this editing device compared to software editors or the Alpha‑Dial because of ease of use and functionality. The PG‑800 allows real‑time editing which enables the user to change sounds while playing live. It is also possible to use the PG‑800 to send editing parameters via MIDI for live MIDI sequencing. This external plug‑in device is extremely hard to find on the used market at a reasonable price. The original retail price in 1985 was $349. The used price today........Fuhgettaboutit!
Retroaktiv has designed a hardware programmer specifically designed for JX‑10 and MKS‑70 synths which have Vecoven 4.xx firmware and PWM boards installed. The MPG‑70 gives access to all of the extra voice features added by the expanded Vecoven mods. Sends MIDI data via SysEx, MIDI CC, or PG‑800 protocol. Can be used with stock a JX‑8P, JX‑10 and MKS‑70 while simultaneously controlling a Vecoven modded Super JX. It sports an OLED screen display and billions of knobs and sliders to tweak. It can be purchased in two different configurations (Fully Assembled ‑or‑ DIY Full Parts Kit). This thing is gigantic and loaded with features!
W. James Meagher worked overtime to craft some amazing BCR2000 control files and template overlays for use with a Vecoven 4.x PWM upgraded Super JX. The PG‑800 and KIWI PE controllers will not work with the Vecoven 4.x PWM upgrade but the BCR2000 will. Plus, the BCR2000 works with an endless list of several other synths including Yamaha, Korg, Kawai, Ensoniq, Akai, Roland, Oberheim... just about anything with a MIDI port! It's a low cost alternative Patch editor and MIDI controller.
Vecoven 4.x: Custom template overlays and *.BCR, *.SYX control files created by W. James Meagher for the Vecoven 4.x firmware are available for downloading in the FILES section at the "Roland JX‑10 and MKS‑70 Synthesizers" Facebook page
MEMORY CARTRIDGE M-64C / M-16C / Symphony 128 S64
NOTE: ALWAYS SET THE PROTECT SWITCH TO THE "ON" POSITION BEFORE INSERTING OR REMOVING AN M‑64C, M‑16C, M‑1024C OR SYMPHONY 128 CARTRIDGE
The M‑64C cartridge is compatible with several Roland synthesizers and drum machines including the Super JX‑10, MKS‑70, MKS‑80, Alpha Juno‑2, JX‑8P, MKS‑20, MKS‑30, TR‑707, TR‑727, TR‑909, DDR‑30, GR‑700, and GR‑77B
The M‑64C has the same design as the M‑16C except that the M‑64C has four times the memory capacity of the M‑16C. The JX‑10 and MKS‑70 can read/import JX‑8P patches that have been stored from a JX‑8P onto an M‑16C [See FAQ Section Above For The Copy Procedure]
The Super JX‑10 can use an M‑16C and M‑64C cartridge with the on‑board sequencer. The M‑16C capacity is 400 notes and the M‑64C capacity is 1600 notes. An M‑64C cartridge holds Patches [A1 through H8], Tones [1 through 50], and 12 MIDI Parameters.
If you have an M‑64C which was used on a different piece of Roland gear (TR‑707, GR‑700, etc...) and you want to use it with your JX‑10 or MKS‑70, set the PROTECT switch to the 'OFF' position. Use the WRITE procedure twice. This same procedure is needed when initializing a blank M‑64C cartridge for the first time
One of the coolest things I've seen in decades is the Vecoven M‑1024C High Capacity Cartridge. This custom built cartridge enables you to store the equivalent of sixteen M‑64C cartridges and also enables you to copy those cartridges between banks. New high capacity RAM IC's have been fused onto an older style Roland cartridge connector to make this one of the most desirable upgrades for your Super JX synth. Finding sixteen used M‑64C cartridges on eBay or elsewhere would easily cost more than $1,000, not to mention the time involved to find them. To use this new invention, you will need the latest Vecoven firmware IC on your Super JX (3.05 and higher or 4.x). EXTREMELY cool! A high resolution label suitable for printing is here, courtesy of W. James Meagher
Roland released three sets of JX‑10 and MKS‑70 Patch and Tone banks on cartridges. These were slightly different than the M‑64C. They are ROM cartridges and have no ON/OFF PROTECT switch. You can't write Patch or Tone data onto these cartridges. These cartridges are bad candidates to use for a Vecoven M‑1024C cartridge upgrade since they lack the write protect switch
M‑64C and M‑16C cartridges use an internal lithium battery to hold the patches and tones in memory. One day that battery will die and the patches will be lost. The life span of the battery is projected anywhere from five to ten years. Mine is still working fine after 29+ years. The internal battery is factory soldered in place onto the cartridge circuit board.
NOTE: DO NOT UNSOLDER THE BATTERY. THERE IS ALWAYS AN EXPLOSION RISK!
To remove the old battery, use a small pair of wire cutters to carefully cut both battery leads from the circuit board then discard the battery. Unsolder the leads left behind and remove all solder from the holes. Ensure the holes are large enough for the leads on the new battery. When soldering the new battery in place, use eye protection, a heat‑sink and make very quick solder joints.
Replacement CR‑1/3N lithium batteries should be ordered with the 'PCB Pins' option. One company selling this specialty battery is;
An instruction sheet and a high‑res schematic
for the M‑64C RAM cartridge is here
High Res Label for Vecoven M‑1024C here
Courtesy of W. James Meagher
Back in the 1980's, a company called Symphony Series, Inc. made a fantastic product called the Symphony 128/S64. The cool thing about this item was that it had two external DIP switches to choose between four banks of Roland cartridge data. It was the equivalent of having four M‑64C cartridges available at the same time for a Super JX, MKS‑80, Alpha Juno‑2 or four M‑16C cartridges available at the same time for a JX‑8P, MKS‑20, MKS‑30, TR‑707, TR‑727, TR‑909, DDR‑30, GR‑700, and GR‑77B. VERY Nice!
Symphony 128/S64 4‑Bank RAM cartridge
Unlike a Roland M‑64C or M‑16C cartridge, the backup battery is easily replaceable and uses a standard CR2032 Lithium 3V Button Cell. It's a simplistic, goofy looking battery holder but... it's easy to use and it gets the job done
Full-page ad from 1980's Electronic Musician magazine here
EV-5 EXPRESSION PEDAL
[ JX-10 ONLY ]
This pedal is a variable resistor for controlling different functions. Depending on how the Control Assign Jacks are setup on the JX‑10, this pedal can function as a real‑time parameter control pedal [UPPER & LOWER BALANCE, PORTAMENTO TIME, TOTAL VOLUME, UPPER & LOWER MIDI MESSAGES] [NOTE: When the EV‑5 pedal is connected to the Control Assign Jack, the assigned Control Assign function cannot be controlled with the Control Assign Knob but only with the EV‑5 pedal]
The EV‑5 retails for the outrageous price of $119 USD and the EV‑7 retails for even more at $279 USD. It is a very simple circuit and it is quite easy to make an equivalent tabletop hand controlled input device using a couple of inexpensive potentiometers, a 1/4" stereo plug, an enclosure and 2‑conductor shielded cable
Instead of buying the 1/4" stereo plug and 2‑conductor shielded cable separately, I suggest that you buy an inexpensive, ready‑made cable on eBay and snip off one end. That way, you'll have a 1/4" plug already soldered onto a cable which will eliminate extra work on your part. I have found this to be the least expensive route. I was able to build one for under $11 - and that includes the shipping charges!
Q: Why would I want to use this instead of a foot controller?
A: I find using a hand‑held expression controller is useful for controlling the synth during mixing sessions plus, I have more accurate control using my fingers instead of my foot. Granted, it's not a true foot controller but, it's still a useful real‑time input device. Of course, the main reason is the cost. It's a savings of $108 which is substantial
The image shown on the right is a dual EV‑5 hand controller. This variation on the original design uses one 1/4" stereo output jack and one 3.5mm stereo output jack (hidden from view). Using output jacks instead of hard‑wiring the output cables was preferred since I already had several existing ready‑made cables. The knobs on top are the Main Controllers (VR1). The knobs on the side are the 'Set‑and‑Forget' Min/Max volume (VR2)
There is an optional add‑on polarity switch mod which enables EV‑5 compatibility with non‑Roland gear. Details for adding this optional switch into the circuit are here
Momentary foot‑switch for controlling different functions. Depending on how the Control Assign Jacks are setup on the JX‑10, the foot pedal can control PATCH SHIFT, PORTAMENTO, CHASE PLAY or UPPER & LOWER HOLD parameters
The DP-6 and DP-8 have been discontinued but the DP‑10 will function in the same manner as the DP‑6 and DP‑8. Just set the Function Select switch to the "Switch" position (located on the side of the DP‑8 / DP‑10). The DP-10 is equipped with a rubber plate on the bottom surface of the pedal. The DP‑8 does not have a rubber plate. This plate improves the stability of the pedal in use, making it less likely to slip even when used on a hard floor. To use, rotate the plate 90 degrees. The DP‑10 has a long 2.2 meter pedal cable. The DP‑8's cable length is 1.3 meters. Other than the points described above, the DP‑10 is identical to the DP‑8 in size and features. Both pedals are equipped with a Function Select Switch to adjust the pedal's functionality:
Half‑Damper Control:
Set the Select Switch to the Continuous Position to use the pedal to control half‑damper capability
Switch Control:
nbsp; Set the select switch to the Switch position to use the pedal as an on/off switch
Quickly step through Patch Parameters using the Alpha-Dial instead of the Number buttons
1) Press the PATCH button
2) Press the PARAM button
3) Rotate the Alpha-Dial to the desired parameter [i.e. AFTER-TOUCH, BEND RANGE, etc...]
4) Press the VALUE button
5) Change the value by rotating the Alpha-Dial
Quickly step through Tone Parameters using the Alpha-Dial instead of the Number buttons
1) Press the TONE button
2) Press the PARAM button
3) Rotate the Alpha-Dial to the desired parameter [i.e. DCO1 LFO, VCF FREQ, etc...]
4) Press the VALUE button
5) Change the value by rotating the Alpha-Dial
Quickly step through MIDI Parameters using the Alpha-Dial instead of the Number buttons
1) Press the MIDI button
2) Press the PARAM button
3) Rotate the Alpha-Dial to the desired parameter [i.e. SYSTEM EXCLUSIVE, CONTROL CHANGE, etc...]
4) Press the VALUE button
5) Change the value by rotating the Alpha-Dial
Set UPPER and LOWER SPLIT POINTS using an external MIDI keyboard [ MKS-70 Only ]
Before you start, make sure the current Patch is set to the SPLIT keyboard mode;
Press the 'SHIFT' button then press the 'C' button and press the 'SHIFT' button again.
Now you are ready to set the Split Points.
1) Press the "PATCH" button
2) Press the "PARAMETER" button
3) Press the "1" button
4) Press the "3" button
5) Press the "VALUE" button
6) While holding down the "C" button on the MKS-70, press a key on the external MIDI keyboard at the same time
7) The new Upper Split Point is now set and shown on the Fluorescent Indicator Panel [FIP]
8) Press the "PATCH" button
9) Press the "PARAMETER" button
10) Press the "1" button
11) Press the "4" button
12) Press the "VALUE" button
13) While holding down the "C" button on the MKS-70, press a key on the external MIDI keyboard at the same time
14) The new Lower Split Point is now set and shown on the Fluorescent Indicator Panel [FIP]
When a MIDI NOTE ON is sent higher than the Upper Split Point, Tone A will be played
When a MIDI NOTE ON is sent lower than the Lower Split Point, Tone B will be played
Set ALL internal Patch Parameters to a BENDER RANGE of 12 [ MKS-70 Only ]
1) You must have ROM IC v1.03 or greater to use this feature
2) This Will Replace All Internal Patch Settings! Save data to an M-64C cartridge if needed
3) Press SHIFT & RIGHT ARROW buttons while powering up the MKS-70
Set ALL internal
Patch Parameters to a BENDER RANGE of 2 [ MKS-70 Only ]
1) You must have ROM IC v1.03 or greater to use this feature
2) This Will Replace All Internal Patch Settings. Save data to an M-64C cartridge if needed
3) Press SHIFT & LEFT ARROW buttons while powering up the MKS-70
MIDI NOTE ON Simulation[ MKS-70 Only ]
Without a keyboard attached to an MKS-70, you can still send a MIDI NOTE ON to the module (useful for module check, bench testing, etc... )
1) Press the ENTER and SHIFT keys simultaneously and the associated LED's will light up red
2) Pressing the number button keys 1 through 8 will produce a sound
and simulate a MIDI NOTE ON
a) Pressing the LEFT ARROW button repeatedly will lower the notes by 1 octave increments in pitch
b) Pressing the RIGHT ARROW button repeatedly will raise the notes by 1 octave increments in pitch
MIDI Bulk Dump*
1) Push the MIDI button then push the WRITE button. The display responds with 'WRITE MIDI'
2) Rotate the Alpha-Dial until the display responds with 'MIDI BULK DUMP'
3) Push the ENTER button
* The JX-10 requires a special utility program such as CPJXWIN (Windows), GENPATCH (Atari ST), ???(Mac)
or a Fred Vecoven Super JX-10 v3.x / v4.x ROM IC Upgrade
MIDI Bulk Load*
1) Push the MIDI button then push the WRITE button. The display responds with 'WRITE MIDI'
2) Rotate the Alpha-Dial until the display responds with 'MIDI BULK LOAD'
3) Push the ENTER button
* The JX-10 requires a special utility program such as CPJXWIN (Windows), GENPATCH (Atari ST), ???(Mac)
or a Fred Vecoven Super JX-10 v3.x / v4.x ROM IC Upgrade
* * * ERROR MESSAGES * * *
ERROR MESSAGE
RESOLUTION
MEMORY PROTECTED
Set the Protect Switch on the MKS‑70 or JX‑10 to the 'OFF' position and, if needed, also set the Protect Switch on the M‑64C to the 'OFF' position
INSERT CARTRIDGE
The cartridge is not properly inserted into the MKS‑70 or JX‑10. Remove and insert the cartridge again if needed
MISMATCH
The cartridge is not appropriate for what you are doing. This can be because of a low battery error on the cartridge or the cartridge is brand new and has not been initialized yet
NOT M-64C
This is shown when trying to write Patch, Tone, or MIDI data onto an M‑16C cartridge. Change to an M‑64C
SELECT NO. 1-50
This appears when trying to write to Tones 51 through 100. Tones 51 through 100 may be edited but may not be re‑written. Select a Tone number from 1 to 50
SELECT NO. 1-32
When trying to call a tone from a JX‑8P cartridge other than 1 through 32, this error message appears. Select a Tone from 1 to 32
MEMORY ERR
Data is not written properly into memory. Check the battery on the M-64C and the internal battery on the MKS‑70 or JX‑10. If this message appears frequently, have the synth serviced by Roland
* * * MISCELLANEOUS * * *
JX-10 MIDI SysEx Is Drain Bamaged
The Super JX‑10 is pretty lame with using MIDI SysEx and the best you can hope for on a factory stock JX‑10 is a dump of all the sounds in the cartridge to your computer and back. JX‑10 SysEx only does a handshaking type of MIDI Bulk Dump or MIDI Bulk Load of its cartridge memory. SysEx Patch and Tone editors will not be able to handle this situation. As far as functionality goes, everything must be sent to the JX‑10's cartridge as a whole, so individual Patch or Tone editing is somewhere between ridiculous and impossible.
To get the most out of your JX‑10, get the new v3.x or v4.x ROM IC upgrade from Fred Vecoven. This new ROM update fixes several problems with SysEx on the JX‑10 and enables communication with editors and librarians. The PG‑800 SysEx MIDI Out feature alone is worth the upgrade. The requirement to always have an M‑64C cartridge plugged in is also eliminated.
Safety Precautions:
Modifications made to any factory stock equipment will always pose an element of risk. Sometimes mistakes are made which are irreversible. Improper soldering and handling of electricity can cause serious injury and damage the synthesizer. Use caution when handling static sensitive devices and the PCB. Make sure you are properly grounded, working on a static‑free workbench or table and wearing eye protection during any soldering tasks. The author is not responsible for any damage or injury resulting from this DIY info. Use this DIY information at your own risk. And, I can't stress enough, the importance of wearing eye protection while soldering. That stuff flies everywhere sometimes!
If you find some of this DIY info useful, please consider donating a small amount. All donations are used for future DIY synth development. Thanks!
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FAQ ‑ Manuals, Service, ROM IC Updates, SysEx, M‑64C Cartridge Copy Functions
I think these two topics are important enough to place at the top of all my synth INFO webpages
Another option is an exciting new development for a modern replacement display created by Guy Wilkinson. A Noritake VFD module can be retrofitted into the existing case of a JX‑10 or MKS‑70. It makes no difference which ROM IC version you have either. It will work with a factory stock system or one with a new Vecoven upgrade. The fonts are super huge, easy to read and it displays a lot more info than the old and boring factory installed display. Another cool feature is that it completely bypasses the old FIP driver coil circuit so there's no need to worry about that time‑bomb anymore. This new display can be purchased pre‑assembled or as a DIY kit. I have installed this display kit in my JX‑10 and it is an incredible enhancement. Highly recommended!!! Guy has an in‑depth website with all the details at 
It's important to note that the "H-M-L LEVEL" 
Springs Used For JX-10 Sharp Keys And Natural Keys Are Different Lengths And Different Tensions
