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Aurora - switched-mode power supply for the Roland MKS-80
Aurora - the world's first replacement switched-mode power supply for the Roland MKS-80, shown here with the original Board B which was soon upgraded to Board Bx with on-board Live-Forever back-up battery mod.

The Roland MKS-80 is an amazing piece of equipment and a lovely sounding machine. As one of the last all-analogue-voiced synthesisers, I am hopeful that Aurora, a replacement power supply for the Roland MKS-80 will keep all of those gorgeous modules still left on the planet, working just a little longer.

Anyone who has a Roland MKS-80 with a power transformer that’s not native to their region, now has the option to upgrade the power supply in their machine and plug it straight into their mains supply, without the need of going through an external transformer.

Anyone with a Roland MKS-80 that has a bad power supply or broken transformer, can now bring a new lease of life to their machine. Also bear in mind that the old FR2 PCBs are now very brittle and prone to dry joints and even cracking.

At the time of writing, some Roland MKS-80s have been operating for thirty-six years! While designed extremely well, the power supplies are stressed systems (as in any machine) and the last thing any MKS-80 owner wants is for the power supply in their machine to go south. IC1 on the original PSU for example, is a M5218L. It's a crucial part of the +5 V supply and the 10 V reference circuit. If this packs up, the  +5 V rail could rise to values that could seriously damage your MKS-80 and even make it unrepairable. As time goes on, the likelihood of this happening, only increases. The +/-15 V supplies which drive the voice boards, are a little more robustly designed.

Aurora switched-mode replacement power supply for the Roland MKS-80

Electronics in general doesn’t like heat. Aurora runs much cooler than the equivalent linear power supply.

Over time, your MKS-80 may develop transformer born hum. This can't be 'filtered' out and you're kinda stuck unless you can acquire a replacement transformer. Hey, you're in luck 'cos Aurora doesn't produce any hum!

Roland MKS-80 transformer
Here's the transformer in a Roland MKS-80. After a couple of decades, they can develop hum.

Originally, Aurora was going to copy the footprint of the original MKS-80 power supply. A single L-shaped board however, would have meant a lot of wastage and potentially necessitate the removal of the front panel to replace the original mains wiring which would have been too short to reach the single PCB.

The solution was to split Aurora into two PCBs; Board A being the main part of the power supply and Board B taking care of mains protection and filtering.

Aurora Board B on mounting bracket
Aurora Board B on mounting bracket. This occupies the space previously taken by the transformer.

I made use of the reinforcing plate that's underneath the original transformer. The size of board B is the same size as this plate. I simply added four M3 mounting holes. This all provides for a very tidy and cost-effective solution that requires minimal reworking of existing wires, etc.

Aurora's 10 V reference source started out as a precision circuit using 0.1% tolerance components and a high-grade op-amp. The results were impressive but later, I changed the design and incorporated a multi-turn trimmer so as to allow for adjustment of the reference which may result from component drift over time.

Provision for fine adjustment of 10 V reference on Aurora Replacement Power Supply for the Roland MKS-80
Adjustment of Aurora's 10 V reference, allows for compensation of component drift over time.

Each supply has it's own status LED. I thought this would be a nice addition and in keeping with the original design although unlike the original, Aurora has a different coloured LED for each supply, including the 10 V reference.

Also note the test points allowing for easy checking of all voltages.

Individual power rail status indicators on Aurora switched-mode power supply for the Roland MKS-80
Aurora has individual power rail status indicators (LEDs) and conveniently placed test points.

So I was going to teach myself Arabic or Mandarin during lock-down 2020 but instead, I kind of decided to design this. It just seemed like a really cool thing to do! 😀 😎

You can read about the development of Aurora Replacement Power Supply for the Roland MKS-80 here.


INSTALLING AURORA

Aurora Tidy Cabling
Keep cabling neat and tidy.

Installing the Aurora boards requires a certain degree of knowledge, experience and skill. I therefore insist that the installation be performed by a suitably qualified technician. Aurora is a power supply that converts mains voltage to several DC voltages that your machine requires. Safety is paramount and although fully tested prior to shipping, I strongly recommend that you test Aurora outside of your machine prior to installation. Since there is mains voltage on both boards, care should be taken that the boards are lifted clear of any work surface during such testing, using for example, PCB stand-offs (spacers).

Removing the original power supply including the transformer also requires a certain degree of knowledge, experience and skill. Remember that these machines are over thirty years to over thirty-five years old.

The voltage distribution headers for example, are soldered to the board. The pins on the headers are not conventional straight pins. They're arrowheads and have a tight fit. Once you're confident that you've removed all of the solder, gently prize  them off the board (GENTLY). I suggest that you wiggle the connector from the component side while observing the underneath so as to ensure that all pins are indeed free.

Header on MKS-80 power supply showing arrowhead pins
+15 V header on MKS-80 power supply showing hollow 'arrowhead' pins.

Don't simply cut the wires to the transformer and the terminals on the original power supply board. Instead, try to unwrap so as to preserve the original length of wire. You may trim some of these later but you don't want to be left short!

Require tools and equipment are as follows:

    • Temperature controlled soldering station (e.g. Weller WE1010)
    • Temperature controlled de-soldering station (e.g. Duratool D00672)
    • Small wire cutters
    • Small pointed pliers
    • Adjustable cable strippers
  • Set of cross-head screwdrivers
  • Small flat-head screwdriver
  • Set of box-spanners (metric)
  • Tweezers
  • Digital multi-meter (DMM)

PLEASE don't use a plumber's or electrician's soldering iron and please don't use a manual solder pump. You'll just wreck things. In fact, if you're thinking of using that kind of equipment, you shouldn't be operating on your MKS-80, let alone installing Aurora!

Aurora showing close-up of SMDs.
Finally Aurora is up and running... beautifully.

A few hints on workflow:

  • Do NOT rush it! Take your time.
  • Check and double check your work after each stage.
  • Do not rely on the status LEDs as indicators of required voltages. Use the test points to measure the voltages with a DMM.
  • When removing screws and nuts from your MKS-80, use a 'gently, gently' approach. You really don't want studs to loosen or threading to shear.
  • Do NOT over-tighten screws and nuts. You're dropping a replacement power supply into a vintage synth module and not building a spaceship that's destined for the outer planets!
  • The 10 V reference has been set by me using a regularly calibrated DMM. Please do not mess with it!!!!!
  • Note the orientation of the headers before you remove them. It's actually not too important other than to keep things tidy except... for P7. Unlike the other headers which each carry a single supply, P7 carries the 9 V supply and a digital ground, to the programmer (MPG-80) port via the output board. It's VERY important that this connector's original orientation is maintained.
  • Your MKS-80 MUST BE EARTHED.  If you have a 2-pin IEC mains socket, you must replace it with a 3-pin IEC C14 socket. The earth pin should be connected to Aurora Board A and Aurora board A should then be connected to the chassis. There's a hole in the lower case in between the mains socket and the side of the MKS-80 chassis which will take a M4 screw. DO IT!!!! Aurora board B must also be connected to this point.

Here's a wiring diagram showing how the two Aurora boards are connected to each other, the mains input, the switch and earth / chassis. Also illustrated is the use of existing (original) wiring as well as some new wiring.

Aurora Wiring
It's really quite straight-forward. You just need to take your time and remember that you're working on a vintage synth module.
Aurora Star Earth Bonding
If your MKS-80 has a 2-pin IEC mains input socket, then you MUST replace it with a 3-pin (C14) IEC socket and connect earths as shown. Also note the insulation boot over the C14 connector.

 

UPDATE - 7th October 2020

Since August's flood, I've had to move ops back home, temporarily. It's very cramped, things are taking longer (it took me two days to find my oscilloscope) but Julie my wife, is amazingly patient and understanding and a big support during this challenging time.

I currently have three MKS-80s in for Aurora and OLED module upgrades. Two of them have already been done but the fourth (a Rev 4 at the back), has a dead voice which I need to fix before I do anything else.

Looks like people are finding out about Aurora
MKS-80 heaven; two Rev 5s and a Rev 4 (ex Trevor Horn), in for Aurora and OLED upgrades.

UPDATE - 2nd December 2020

So the past few months has seen more than a few Aurora sales and installations. Many customers whose units I've had in, have asked if I could also install my Live Forever memory back-up battery mod and it got me thinking.

Aurora has two boards. Board B comprises mains protection and filtering so, not a lot. With a little nudging, I was able to fit a CR123a battery holder on to the PCB and so Aurora Bx Board was born! Read more about it here.

New Aurora Bx board with large capacity back-up battery
Aurora Board Bx with on-board back-up battery mod, is now available.

UPDATE - 24th December 2020

Aurora installation instructions are now available in German.

Die Installationsanleitung für Aurora ist jetzt in deutscher Sprache verfügbar.


UPDATE - 24th April 2021

Aurora is now offered with the optional V06 data cartridge re-enforcement bracket. Such a cool solution to a problem that many Roland MKS-80 owners will be familiar with, the V06 basically strengthens an undamaged cartridge slot and reinforces a broken one by putting 2mm of solid steel behind it!

V06 Bracket for Roland MKS-80 Data Cartridge Slot
V06 bracket for Roland MKS-80 broken data cartridge slot assembly.

Existing Aurora customers take note; once your Roland MKS-80 is open, V06 can be installed in a few minutes, with just a M3 (5.5mm) nut-runner.

Read more about the V06 here.


UPDATE - 9th August 2021

Here are a few pictures of customers' own installations.


Plasma Music Limited -

I'm deeply concerned about the environment and the exploitation of labour and so  I always use local manufacturers in preference to the Far East, with the following in mind:

  1. I can be confident that workers are treated fairly and earn a proper wage.
  2. I can be confident of the standard of quality of each item that is delivered to me.
  3. Communication is important and using local manufacturers, all correspondence is quick and understandable.
  4. I believe in supporting the local economy.
  5. I can be confident that the disposal of manufacturing waste is managed properly and in accordance with national and EU law.
Environmental considerations of delivering Aurora
Remember the 'Colours of Benetton' adverts from the eighties? A little shock, horror to make the point. So rest assured that Aurora boards are manufactured here in the UK by Minnitron Limited.

Using local manufacturers isn’t the cheapest option but the above points are important to me. I hope that they’re important to you too.

Please don't hesitate to contact me if you have any questions regarding the Aurora Replacement Power Supply for the Roland MKS-80 or, if you want to buy Aurora or book in your MKS-80 to have it fitted, please check out my store.

Following on from my post covering the installation of a replacement power supply into a Roland MKS-70, I decided to do another post on a whole bunch of cool Roland MKS-70 upgrades which I discovered during lock-down 2020. Apologies if some stuff is kinda repeated.

Back in April 2020, I got a Roland MKS-70 in for repair. It was powering up but wasn’t booting. While replacing original components that were over thirty years old on the power supply, another MKS-70 came in with err… power issues.

This all happened during lock-down so progress on the repairs was kinda slow. I did however, have lots of time to see what I could find on-line.

I very quickly came across supersynthprojects.com and over a period of days, got to know Guy Wilkinson, a vintage synth enthusiast with a very relevant background. Guy has developed a switched-mode power supply for the JX-10 and MKS-70.

Guy Wilkinson's switched-mode power supply installed intoa Roland MKS-70
A P0004 switched-mode replacement power supply installed in a Roland MKS-70. Look... no transformer!

Guy also supplies a variety of displays, one of which particularly caught my attention, the Super-JX OLED upgrade display. As many Super-JX owners will know, the original vacuum fluorescent display (or VFD) as well as the FIP coil that drives it, is just about impossible to get hold of now. VFDs and FIP coils fail, so any potential replacement is well worth checking out, especially if it's going to be OLED cool.

Roland Super-JX upgrades - Guy Wilkinson's Super-JX OLED upgrade module
Guy Wilkinson's Super-JX OLED module.

I've always wondered why some people use the adjective "sexy" to describe tech'. Guy's Super-JX OLED looks stunning and now I know. I just can't stop looking at it! 😛

Super-JX OLED upgrade module installed in Roland MKS-70

As I continued my research into the world of Roland Super-JX upgrades, I came across  vecoven.com and the Vecoven PWM upgrade; a kit which provides the Super-JX sounds with pulse-width modulation. WHAT!?!?!?!

Fred Vecoven sells the PWM upgrade as a self-assembly kit comprising two small PCBs (one for each voice board), lose components, three EPROMs and two replacement 80C320 processors (again one for each voice board). An option to buy populated PCBs is also available.

Neither the self-assembly kit or the pre-assembled PCBs kit are however, supplied with cabling or connectors, presumably because there are several potential mounting options. Guy's website has detailed installation instructions for Fred's PWM kit, both for the JX-10 and MKS-70.

Below is a pair of Vecoven PWM upgrade PCBs which I have made up myself.

Roland Super-JX upgrades - Vecoven PWM kit.
Assembled PCBs of the Vecoven PWM upgrade for Roland MKS-70 and JX-10.

The keen and eagle-eyed will have noticed that the ICs aren't soldered directly to the PCB and that instead, I've chosen to use turned-pin sockets; always a good idea!

Fred Vecoven has also rewritten the Super-JX firmware and has developed a flash upgrade module which, apart from increasing the memory to the equivalent of thirty-two Roland M64C cartridges (yes, that's right... 32 x M64Cs), allows firmware updates via MIDI. Fred's firmware also gives you some control over how Guy's displays work. Hey, is that teamwork or what?

Roland Super-JX upgrades - the Vecoven Super-JX Flash Module
Vecoven Super-JX flash module (highlighted in red) installed in a Roland MKS-70.
Vecoven Flash Module Installed In Roland MKS-70
Voice boards lifted for a close-up view.

Well it just so happens that I also have a Roland MKS-70 (yeah, I know... you're really surprised, right?) and all this stuff just sounded soooo exciting. Within a few days, I ended up with a switched-mode power supply PCB and an OLED kit from Guy and a PWM kit and a Super-JX flash module from Fred. My wife wasn't happy.

And I thought lock-down was going to be oh soooo boring!

I had to buy all the components for the P0004 power supply but conveniently, Guy has a very detailed bill of materials (BoM) on his website. This made components purchase very easy. The OLED module came fully assembled and Guy e-mailed me instructions on how to install it. As previously mentioned, Fred's PWM kit doesn't include connectors and cables so I also had to buy some bits to get this going.

Getting to know Guy and Fred was a privilege. In fact, I eventually struck up a deal with Guy and I am now offering ready-built versions of his P0004 switched-mode power supply board, as well as an installation service for this fantastic upgrade and his Super-JX replacement displays.

Click here for my prices:

If you're fitting the switched-mode power supply module yourself and your MKS-70 or JX-10 has a 2-pin IEC mains input socket, then you must replace it with a 3-pin IEC mains input socket. The replacement switched-mode power supply MUST be connected to earth as must the chassis of your Super-JX.

I offer a comprehensive earth bonding kit comprising the following:

    • 1 x IEC 3-pin chassis socket.
    • 1 x insulating boot for IEC socket.
    • 2 x Pre-cut earth leads terminated at one with earth tag.*
    • 1 x M3 earth tag (for one side of IEC socket).

*One earth lead connects IEC earth to chassis via one of the screws that secures the IEC socket. The other earth lead connects the P0004 power supply to the chassis via any M3 screw.

It is paramount that if fitted, a 2-pin IEC mains socket be replaced with a 3-pin IEC mains socket and that the chassis and the P0004 are connected to earth.
It is paramount that if fitted, a 2-pin IEC mains socket be replaced with a 3-pin IEC mains socket and that the chassis and the P0004 are connected to earth.

Installing these Roland Super-JX upgrades into my own MKS-70, was hard work but I had a lot of fun doing it and... I got to know a couple of seriously intelligent dudes.

My humble contribution to the awesome work that Guy and Fred have done, is a simple bracket which makes mounting the PWM boards into a MKS-70 a little easier. IMPORTANT: Since the bracket secures to the transformer mounting studs, it can only be fitted if Guy's P0004 switched-mode power supply is also installed.

Custom mounting bracket for Vecoven PWM mod for MKS-70
Custom mounting bracket for Vecoven PWM kit in Roland MKS-70. The benefits of using this include no holes to be drilled in the voice-boards, makes general maintenance so much easier and of course your MKS-70 can be put back to factory any time.
Custom mounting bracket for Vecoven PWM mod for MKS-70 installed
An elegant solution (even if I say so myself), my custom bracket makes installing the Vecoven PWM mod into the Roland MKS-70, so much easier.

The IDC connectors I've used, don't have the tidy fold-over clamp (retainer). That's because those ones are too high and this neat little mounting solution won't work as the whole assembly will simply be too high to fit in the MKS-70's 2U case.

The other point to note is that the V01 mounting bracket puts the Vecoven PWM daughter-boards, in very close proximity of the voice-boards. Hence and unlike if mounting the Vecoven PWM daughter-boards to the voice-boards, vertical and NOT right-angle IDC headers must be fitted to the PWM boards.

I wasn't going to offer this bracket as an item as it didn't seem worth it but I've been persuaded to get some made up and so I’m selling them with fixing hardware (screws, washers, spacers), as a kit for 27.60 GBP. This includes tax but excludes shipping. If you fancy one, you can either buy now from here or just message me.

Note that the bracket isn't necessary when fitting the PWM kit into a JX-10.

Inspired by Guy's switched-mode power supply, I've proposed a couple of joint projects so watch this space!


!!! WORDS OF CAUTION !!!

These machines are over thirty years old. As such, nuts and screws have seriously bedded in. You may find some glue around the nuts and even some signs of corrosion.

If you're upgrading one of these machines yourself, please take care when undoing nuts and screws. The studs which secure the massive heat-sink plate of the original power supply and also the transformer for example, can become lose. When trying to remove the nuts on the inside of the chassis, they'll just spin around and  they won't undo. If this happens, you'll need a pair of mole-grips to carefully hold the studs from underneath the case while gently loosening the nuts with a box spanner on the inside of the case.

Mole grips can be a little aggressive so you might want to think about protecting the case with some thick tape. Put the tape around the lug of each stud and also put some tape on the tips of the jaws of the mole-grips. I found thick masking tape best for the case and lugs and cloth (or gaffer) tape is good on the mole-grips.

Taped mole grips to protect case
Doesn't look very pretty but helps protect your case.

When re-assembling, I would recommend replacing the nuts and soaking them in a lubricant like WD-40 prior to fitting.

!!! NOT FOR THE FAINT HEARTED !!!

The second point I should make is that with the exception of the Vecoven Flash module, all other upgrades mentioned here, require some considerable experience of soldering, desoldering, working with surface-mount devices and respecting electrical safety and electrostatic sensitivity. You should also be prepared to drill into existing PCBs and / or original chassis metal work.

!!! Remember, if you get it wrong, you might permanently damage your synth !!!


Today, my MKS-70 still looks pretty much as it did when my good friend Rob donated it to me, several months ago. Under the bonnet however, it’s quite a different beast. The sound is still lush and beautiful but...

  • As a result of installing Guy’s P0004 switched-mode power supply, not only has reliability and longevity been increased but this machine can be plugged straight into just about any mains supply on the planet.
  • The sounds can now benefit from pulse-width modulation thanks to the Vecoven PWM upgrade.
  • The Vecoven Super-JX flash module has increased the memory to a ridiculous amount; more patch changes and less SysEx transfers!
  • Firmware updates can now be performed over MIDI.
  • Guy's Super-JX OLED display looks quite simply, beautiful. To the experienced Super-JX user, it might be the only indication that something is err... different.
  • The Super-JX OLED will live much longer than the original VFD and FIP coil which can only give peace-of-mind.
Roland MKS-70 Fully Upgraded
Boot screen of fully upgraded Roland MKS-70.

LIVE FOREVER BATTERY MOD

Live Forever battery mod at Plasma Music

This is something I do which isn't unique to the Roland MKS-70 and which can be fitted into almost any synthesiser or effects processor. It's NOT literally a 'Live Forever' battery mod as nothing obviously lives forever. The chances are however, that it'll out live you!

The damage caused by battery leakage can be irreversible. It's not just a case of losing all those tones and patches that you err... forgot to back up. Battery leakage can seriously damage the PCB on which the battery is mounted; usually the CPU board in most machines.

I mount a high-capacity lithium battery off any PCB giving you the following three main benefits:

  1. Will last a lot longer than the standard CR2032 which is found in most synthesisers and effects processors.
  2. Mounted off-PCB so in the remote event that it does leak, sensitive electronics inside your equipment is protected.
  3. Positioned such that battery voltage can be easily checked by only removing the top of your machine.

If you missed it earlier, all my prices can be found here.

SUPER-JX EDITORS, CONTROLLERS, PROGRAMMERS

Anyone with a Super-JX will be aware of the Roland PG-800, a programmer / editor, specifically for the JX-10 and MKS-70. Today, PG-800s are hard to find, relatively expensive and quite honestly, you'd be lucky to find one in really good condition. I'm not talking cosmetically but electronically and it's worth bearing in mind, that parts are becoming ever scarcer.

Thankfully, a company called RetroAktiv makes a small collection of hardware programmer / editors for several popular vintage synthesisers... including our beloved Super-JX.

I don't have one of these myself but I've heard only good things about the RetroAktiv MPG-70. On top of that... damn, it looks good!

At 875 USD, the RetroAktiv MPG-70 costs a couple of hundred USD more than an original Roland PG-800. The thing is, even if you forget about the fact that this box is going to be considerably more reliable than thirty-something year old electronics, you're getting a lot more for your money and (I'm going to say it again) it just looks awesome.

If you're still not convinced, then RetroAktiv also makes a smaller Super-JX editor  called the MPG-8, which retails for just 349 USD.

One of the many features of both of these controllers, is full compatibility with the Vecoven PWM upgrade and firmwares.

For some time now, I've been using a plug-in called Ctrlr. It’s basically an open-source environment for Windows, OS X and Linux, which allows users to develop programmers and editors for just about anything. Many users share their ‘panels’ on the Ctrlr website and I was so surprised to find a panel specifically for the Vecoven V.4 firmware upgraded Roland Super-JX. This doesn't really fall into the category of Roland MKS-70 upgrades as such but I think it still deserves a mention. Available for Windows and OS X, 32 or 64-bit and in plug-in or stand-alone format, you really need to check this out. Oh and it's free! 😀

Ctrlr Panel for Vecoven Super-JX

The RetroAktiv programmers will work with Super-JXs running standard (factory)  firmware although some sliders and knobs won't do anything as there's no PWM to modify, for example. The Ctrlr panel above will ONLY work with Vecoven version 4 firmware. While I've seen Ctrlr panels that'll work with Vecoven version 3 firmware, I haven't come across anything that'll work with bog standard Roland firmware.

It's been most reassuring to discover that I'm not alone, that there's a whole community out there that share my appreciation and even passion, for this underrated monster of a synthesiser. I'm so grateful to people like Guy, Fred and the RetroAktiv crew, who after more than thirty years from it's launch, have embraced the potential of the Roland Super-JX, developing upgrades that ensure this magnificent machine lives on.

I'd love to contribute what I can so please don't hesitate to contact me if you'd like more information on any of the Roland MKS-70 upgrades (or JX-10 upgrades) mentioned here. I'd love to hear from fellow fans of this awesome synth. 😎

In the meantime, here's a few links that you might want to check out:

https://supersynthprojects.com - This is Guy Wilkinson's website full of seriously useful information about the Roland Super-JX.

http://super-jx.com/ - Sites like this, truly keep the legend alive!

http://www.vintagesynth.com/roland/jx10.php - An excellent reference site.

https://www.facebook.com/groups/SuperJX/ - You just knew that there had to be a Facebook group, right?

https://www.facebook.com/groups/1837407526336417/ - ...or two!!!

Retroaktiv MPG-70 hardware Super-JX programmer


UPDATE: 11th July 2020

Wow! Since I put up this post, things have got a little busy.

Super-JX mods at Plasma Music
Three MKS-70s and yes, well done! You've spotted the MKS-80 in the foreground.
Super-JX mods and upgrades at Plasma Music
This machine is having my Super-JX upgrade bundle fitted.

UPDATE - 17th August 2021

Nebula balanced outputs jack board for the Roland MKS-70
This is Nebula, a new jack board for the Roland MKS-70 with upgraded MIDI and balanced outputs.

Today I launched Nebula, a replacement jack-board for the MKS-70 with upgraded MIDI and balanced outputs.  Read all about it here.

So in case your Marshall JMP-1's memory gets screwed up, if you just want to start from a clean slate or you've just changed the memory back-up battery, here's the Marshall JMP-1 factory reset procedure.

WARNING: Implementing this procedure will permanently delete all user-made changes to any patches.

Marshall JMP-1 Factory Reset

  1. Switch off JMP-1 via the power button on the far right.
  2. Hold down the OD1 button and the CLEAN 1 button.
  3. While holding down these buttons, switch on the JMP-1.
  4. Wait a few seconds while the display flashes and then release the OD1 and CLEAN 1 buttons.

Now then, you're JMP-1 might NOT reset! Yes, that's right. If your machine is locked, performing a factory reset will be useless unless you unlock your JMP-1 first.

To check the 'SAVE' status of your JMP-1, simply try to save a patch. If the display shows 'St L', then your JMP-1 is locked and you will need to unlock prior to performing a factory reset.

Unlocking is simple. Just follow this procedure:

  1. Try to save a patch.
  2. While 'St L' is displayed, press the <CHANNEL> button.
  3. The unit will unlock and the display will show the current channel to save to ex: "St 01".
  4. You can now perform a factory reset as above.

I  hope this Marshall JMP-1 factory reset procedure helps a few people but if you get seriously stuck, just message me. 🙂

If you want to read more about what I do with JMP-1s, like general service and repair, finding a permanent solution for the skipping data entry knob thing, sorting out the humming transformer issue and offering nice, classy replacement knobs, then please check out some of my other posts:

Marshall JMP-1 Service
Marshall JMP-1 Needs Attention
Eclipse Marshall JMP-1 Data Encoder Fix
Marshall JMP-1 Nuts, Knobs and Bezels

Marshall JMP-1 Knobs Nuts and Bezels

Apart from service and repair, I sell a few bits 'n' pieces for the Marshall JMP-1 which you may find of interest. Check out my on-line store to find out more.


UPDATE - 21st September 2021

At last!!!! 😀 My PML-TX01 replacement (and upgraded) transformer for the Marshall JMP-1 is finally here! Running much cooler and producing considerably less hum than the original TXMA-00014 my PML-TX01 is an upgrade worth considering.

And here it is... my PML TX-01 transformer for the Marshall JMP-1
And here it is... my PML TX-01 transformer for the Marshall JMP-1