This page contains U-20 information about;

U-20 ZONE FAQ - Manuals - Troubleshooting - Factory Presets - Aftertouch
U-20 ZONE TESTS - RAM - Buttons - Aftertouch - LCD - MIDI - Batteries - LED's
U-20 ZONE RED EXOPY SYNDROME - "Run Away! It's the BLOB!!!"
U-20 ZONE ROM IC VERSIONS - ROM Revisions - Bug Fixes
U-20 ZONE SPECS - Dimensions - Power - RAM
U-20 ZONE ACCESSORIES - PCM Cards - RAM Cards - Pedals
U-20 ZONE ERROR MESSAGES - Common Error Messages And Troubleshooting
U-20 ZONE For additional info about the U-220 Sound Module, visit the BigRedRoo U-220 Page

U-20 ZONE     U-20 ZONE U-20 ZONE - BATTERY U-20 ZONE     U-20 ZONE

ANIMATED_STAR I think this topic is important enough to place at the top of all my synth INFO webpages

I buy a LOT of broken gear 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

* * * FAQ: U-20 * * *

"The U-110 (or, rather, its unreleased prototype, the T-110) is the ancestor of almost all Roland's synths and workstations from 1991 onwards. This makes it one of the most significant synths ever released. The problem with the U‑110 was that its digital‑to‑analogue converters were rather noisy. This was cured in 1989 with the release of the U‑220, which sounded much more 'high‑end'... the U‑20... possibly the first affordable keyboard that you could take on stage to produce convincing piano, organ, strings, brass, drums... as well as many other pads, effects, leads, basses and other important sounds. Leaping from the back pages to the front of Roland's catalogues, the U‑20 was a winner." --- Sound On Sound, 2005 ---

The most common praises about this keyboard are the realistic piano sounds within. In fact, some people made their U‑20 purchase decision based on Patch I‑11 Acoust Piano. If you go searching the Internet for the U‑20, you will find that this is one of those keyboards that people either really, really like... or totally despise. The U‑20, U‑220 and U‑110 are infamous as having the absolute worst user interface... ever. The chaotic and cryptic Owner's Manual sealed the deal and quickly placed the U‑20 in a Top 10 List - "Most Hated Keyboards Of All‑Time". Personally, I really, really like this keyboard. It may be old technology, but I have been using it as my main keyboard controller since 1990, took it on the road for several live gigs, and it has always performed well. One of the sounds which shows off the versatility of this keyboard is Patch I‑83 Velo Combi. Playing the keyboard very soft will produce a piano sound, playing with medium velocity makes a ethereal Vox sound and playing the keys hard creates a Super Strings sound. Love it!

A common user complaint is that the built-in Arpeggiator does not send notes out via MIDI. This simply is not true. In fact, it is quite easy to setup the U‑20 to output Arpeggiator notes via MIDI (see page 92 of the Owner's Manual). Other complaints are faulty key sensors not triggering notes, slow response times, lackluster Aftertouch response and the Red Epoxy Syndrome. I can't address any issues with faulty key sensors or the Red Epoxy Syndrome because I have had no such problems. For issues with slow response times, see this section. The Aftertouch on my U‑20 has a definite problem. The Aftertouch on my Alpha Juno‑2, JX‑10 and S‑50 stopped being responsive over a period of time. It's a common problem. After cleaning the Aftertouch strips, those problems were resolved immediately. From a repair standpoint on the U‑20, to me it looks like a lost cause (see Aftertouch below). I have seen documentation on the Internet about an Aftertouch mod for the U‑20 which involves changing some resistor values on the Bender Board. I have not attempted to fix the U‑20's Aftertouch issue or clean the contact strips... yet. I'm still looking into this problem and will report back in time... when I get the time

Where Can I Find Owner's Manuals For The U‑20, U‑220, U‑110, D‑70, and Rhodes Model 660/760 Synths? HAZARDOUS MANUAL
The U‑20, U‑220, and U‑110 Owner's Manuals are some of the worst manuals ever written. They are chaotic and extremely difficult to follow. The complicated menu architecture of the U‑20 deserves a better guide but this is all that is available online

        SUPER JX U-20 Owner's Manual (v.94-8)

FREE Owner's Manuals for almost every synthesizer and effects device can be found at

        SUPER JX midimanuals.com
Where Can I Find Service Manuals And Schematics?         SUPER JX U-20 Service Notes (v.89-6)

Gigantic collection of Service Manuals w/schematics at this link. The highest quality PDF's on the Internet

        SUPER JX synfo.nl
What Do The "U‑Series" Modules and Keyboard and Sound Like?         U-20 Demo Song U-20 Demo Songs         U-20 Demo Song U-220 Demo Songs        U-20 Demo Song U-110 Demo Songs

        All 64 factory preset Patches and a selection of Timbres         SUPER JX SynthMania
How Do I Fix A U‑20 Or U‑220 When Garbage Characters Are Displayed On The LCD Screen And The Keyboard Does Not Play Notes? GOOD NEWS FOR THE U-20 LCDThe Good News
If the characters showing on the LCD are a mix of symbols, letters and numbers, chances are good this is an easy fix. It's probably one of these three problems;

1) The internal backup battery has died and all the Patches have turned into random bits of data
    Solution: Replace the internal battery and reload the Factory Preset Patches (or an alternate Patch bank)

2) A corrupted SysEx file was loaded or a SysEx file was interrupted during the load process
    Solution: Reload the Factory Preset Patches (or an alternate Patch bank)

3) The system was initialized, a circuit board was unplugged, inactivity in storage, etc...
    Solution: Reload the Factory Preset Patches (or an alternate Patch bank)

I'm always amazed at how Roland designed some of the behaviors of the U‑20, U‑220 and other synths. This was considered as "normal" operation... reset the synth, everything on the screen turns into garbage and the keyboard is useless. Not even a one line courtesy message like, "Load Patches". Yay! Go Roland ;^)

If the LCD display shows a bunch of thin vertical lines, the problem is more serious and will most likely require a LCD replacement screen or more extensive servicing by a Roland Authorized Service Center

* Bonus U‑220 / JV‑880 Trivia
Replacement parts for old synth gear like the U‑220 and JV‑880 are nearly impossible to find these days. If you're lucky, sometimes you can find parts on different synths which are interchangeable. Even though the U‑20, U‑220 and U‑110 all share similar electronics, all three use a different LCD screen and they can't be swapped with one another. However, the U‑220 uses the identical LCD display (P/N: 15029505) as the Roland JV‑880 synthesizer. These are a direct drop‑in replacement and no rewiring is needed. More interchangeable part numbers for the U‑20 and U‑220 are available at this link
How Do I Restore The U‑20 Factory Preset Patches Or Load An Alternate Set Of Patches? To restore the Factory Preset Patches, you will need a Mac, PC or LINUX computer with a generic SysEx loader program. It is also possible to quickly restore the Factory Preset Patches if you have an optional RAM Data Card*

[ WARNING!!! Everything in the internal memory will be erased! ]

To perform a Bulk Load

1) Use your computer's SysEx program to SEND the factory preset file U-20_Factory_Presets.SYX. The load process is automatic

2) The LCD display will show Receiving Exclusive. during the load process

3) If the Patches won't load or if you receive a MIDI Buffer Full! error message, try adjusting the speed of your SysEx program**

If the Bulk Load procedure did not work, verify the following***

     Connect MIDI Out and MIDI In cables between the U-20 and the computer
     Is the U-20 set to the correct SysEx Channel and is SysEx turned on?
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR
          Use [ △ ]  VALUE  [ ▽ ] to set SysEx Device ID = 17
          Press [ ▻ ] CURSOR twice
          Press [ △ ]  VALUE to set Rx SysEx = ON
          Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

* Info about restoring Factory Preset Patches from an optional RAM Data Card here

** The MIDI Send and Receive settings on your computer might be too fast for the U‑20 MIDI buffer to handle. The U‑20 was designed back in Medieval times when the processor speed of a home computer was 50MHz... much slower than the models of today at 4GHz. Try setting the MIDI buffer size in your computer's SysEx program to a smaller value. Recommended values for Snoize, Bome and MIDI‑OX are 390ms

*** Verifying SysEx is only needed once (until the next time SysEx Device ID or Rx SysEx are changed)
How Do I Save All Of The Internal Patches And Timbres Of A U‑20 / U‑220? To save all 64 Patches and 128 Timbres, you will need a Mac, PC or LINUX computer with a generic SysEx saver program

To Perform A Bulk Dump On The U‑20

     Press [ DATA ] then use CURSOR [ ▻ ] to select Bulk and press [ ENTER ]
     Press [ ▻ ] to select Internal and press [ ENTER ]
     At this point, initiate your computer's SysEx program to capture the incoming SysEx data stream
     Use [ ▽ ]  VALUE to select All and press [ ENTER ]
     The LCD display will show"Transmitting Sysex."during the Bulk Dump process
     When the Bulk Dump process has finished, the LCD display will briefly show"Function Complete."
     Use your computer's SysEx program to save the Bulk Dump as a *.SYX file
     Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

To Perform A Bulk Dump On The U‑220

     Press [ DATA ] then use CURSOR [ ▻ ] to select Bulk and press [ ENTER ]
     Press [ ▻ ] to select All and press [ ENTER ] and the screen displays "Data/Bulk/All" twice
     At this point, initiate your computer's SysEx program to capture the incoming SysEx data stream
     Press [ ENTER ] again and the LCD display will show "Transmitting Sysex." during the Bulk Dump process
     When the Bulk Dump process has finished, the LCD display will briefly show "Function Completed."
     Use your computer's SysEx program to save the Bulk Dump as a *.SYX file
     Press [ EXIT ] three times to resume normal play mode

If the Bulk Dump procedure did not work, verify the following*

     Connect MIDI Out and MIDI In cables between the U-20 and the computer
     Is the U-20 set to the correct SysEx Channel and is SysEx turned on?
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR
          Use [ △ ]  VALUE  [ ▽ ] to set SysEx Device ID = 17
          Press [ ▻ ] CURSOR twice
          Press [ △ ] VALUE to set Rx SysEx = ON
          Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

          * Note: Verifying SysEx is only needed once (until the next time SysEx Device ID or Rx SysEx are changed)
I Can't Get The U‑20 To Communicate With My Computer When Using A Librarian, SysEx Program Or Sequencer. What Should I Check? NOTE: Sometimes, the MIDI send and receive settings on a computer are too fast for the U‑20 MIDI buffer to handle. If you experience communication errors such as MIDI Buffer Full!, try setting the MIDI buffer size in your computer's SysEx program to a smaller value

Is the U-20 set to SysEx Device ID = 17?
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR
          Use [ △ ]  VALUE  [ ▽ ] to set SysEx Device ID = 17
Is the U-20 set to Rx SysEx = ON?
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR twice
          Press [ △ ]  VALUE to set Rx SysEx = ON
          Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode
Is the computer Sound Card, MIDI Controller, SysEx Librarian, etc... set to MIDI Channel 1?
Is the computer Sound Card, MIDI Controller, SysEx Librarian, sending MIDI data to the U‑20?
Make sure the patch librarian or SysEx program can send and receive SysEx data to and from the U‑20
Do you have two MIDI cables connected? Two are required because SysEx uses both MIDI IN and MIDI OUT
How Do I Change The Internal Back‑Up Battery? CR2450 BatteryYou can test the voltage of the internal battery without opening the U-20. How cool is that?!?
See Internal RAM Test on this page

I recommend that you take your keyboard to a Roland Authorized Service Center because installing a new battery is a tedious task. Out of 12 synths, samplers and keyboards, replacing the battery on a U‑20 was the most difficult one I have encountered to date. 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;

         U-20 U-20 Battery Replacement Guide
How Do Initialize The U‑20, U‑220 and U‑110 And Return It To A State Of "Factory Fresh"? !!! WARNING !!!
This Will Render Your Synth Unplayable Until Patches Are Reloaded.
Everything In The Internal Memory Will Be Erased. Everything... As In EVERYTHING!
Back-up Your Patches Before Initializing Your Synth.


U-20 Factory Reset (see WARNING!!!)
     Press [ PART ] and [ RHYTHM ] simultaneously to enter ROM Play Mode
     While holding [ MARK ] and [ JUMP ], press [ ENTER ] for Test Mode
     While holding [ JUMP ], press [ NUMBER 7 ] and the screen displays "15. Memory Initialization"
     Press [ ENTER ]
     Press [ VALUE △ ] to confirm
     While holding [ JUMP ], press [ EXIT ] and repeat to exit Test Mode
     Load The Factory Preset Patches via SysEx or RAM Data Card

U-220 Factory Reset (see WARNING!!!)
     Press [ JUMP ] and [ VALUE Δ ] simultaneously to enter ROM Play Mode
     While holding [ MARK ] and [ JUMP ], press [ ENTER ] for Test Mode
     While holding [ MARK ], press [ PART INST ◅ ] and the screen displays "11. Memory Initialize"
     Press [ ENTER ]
     Press [ VALUE △ ] to confirm and the screen briefly displays "Function Completed."
     While holding [ JUMP ], press [ EXIT ] and repeat to exit Test Mode
     Load The Factory Preset Patches via SysEx or RAM Data Card

U-110 Factory Reset (see WARNING!!!)
     Turn the power on while holding the [ PART ] and [ EDIT ] buttons
     64 Factory Preset Patches are automatically loaded by default via the onboard ROM IC
I Plugged In An SN‑U110 PCM Card. How Do I Access The Tones On The PCM Card? See the section titled  SUPER JX PCM Expansion Cards
How Do I Adjust The Display Contrast Of The LCD Screen? U-20
     Press [ EDIT ]
     Press the [ ] CURSOR several times to select SETUP (blinks) then press [ ENTER ]
     Use the [ ] CURSOR [ ▻ ] to select LCD (blinks) then press [ ENTER ]
     Use [ △ ]  VALUE  [ ▽ ] or the C2 Value Slider Knob to adjust the LCD Contrast (0 - 15)*
     Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

     Press [ EDIT ]
     Press the [ ] CURSOR to select SETUP (blinks) then press [ ENTER ]
     Use the [ ] CURSOR [ ▻ ] to select LCD (blinks) then press [ ENTER ]
     Use [ △ ]  VALUE  [ ▽ ] to adjust the LCD Contrast (0 - 15)*
     Press [ EXIT ] three times to resume normal play mode

     Press [ EDIT ]
     Press the [ ] [ ▻ ] buttons to select UTIL (blinks) then press [ ENTER ]
     Press the [ ] [ ▻ ] buttons to select LCD (blinks) then press [ ENTER ]
     Adjust the contrast using the [ DEC ] [ INC ] buttons
     Press [ EXIT ] three times to return to the Play Mode

   * The contrast setting is saved the instant you change (just like all the other U-20 / U-220 settings)
     The new setting is retained even if the U-20 / U-220 is powered off
Why Does My U‑20 Act Sluggish? This could be caused by one or a combination of these three issues;

1) If the setting for SysEx Patch Dump is turned ON, this will cause the U-20 to spend unnecessary cycles sending SysEx data to the MIDI ports. Set this to SysEx Patch Dump = OFF and you should notice improved response times when cycling through patches
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR two times
          Press [ ▽ ]  VALUE to set SysEx Patch Dump = OFF
          Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

2) Earlier versions of the U-20 ROM IC experienced delays which occurred when
  • Fast, dense chords are played
  • Large amounts of streaming MIDI data fill up the U-20's MIDI buffer
  • The setting Rx SysEx = ON
U-20's upgraded to the final ROM IC v3.03 will correct most delay issues

Too many Program Change or Control Change messages could be overloading the MIDI buffer
If upgrading to a newer ROM IC is not an option, try setting Rx SysEx = OFF*
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR three times
          Press [ ▽ ]  VALUE to set Rx SysEx = OFF
          Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

3) If you have more than three MIDI devices plugged into the your chain of MIDI THRU connectors, use an optional MIDI THRU box

* Remember to set Rx SysEx = ON when saving/loading Patch banks or using your computer for sequencing
Other Than A Keyboard, What Are Some Of The Main Differences Between The U‑20 And The U‑220 / U‑110 Sound Modules?
  • The U-220 and U-110 are unable to use M-256E or M-512E PCM Data Cards to store Patches and Tones
  • Several owners report that the U-110 is much noisier than the U-20 and U-220
  • The U-20 has two 1/4" input jacks for connecting an EV-5 Expression Pedal and a DP-10 / DP-2 Hold Pedal
  • The U-20 and U-220 have 2 PCM Expansion Card Slots. The U-110 has 4 PCM Expansion Card Slots
  • The U-110 has a different DSP effects structure than the U-20 and U-220
  • The U-110 has a lower sample playback rate than the U-20 and U-220
  • The U-110 has 2MB Internal ROM. The U-20 and U-220 have 3MB Internal ROM
   Synth            Sample       PCM Card     Data RAM     Assignable         Built-In          Internal
   Model        Playback Rate     Slots      Card Slots     Outputs          DSP Effects        ROM Size
   -----        -------------    --------    ----------    ----------    -------------------    --------
   U-20             44kHz           2            1             2         Reverb/Chorus/Delay      3MB
   U-220            44kHz           2           None           4         Reverb/Chorus/Delay      3MB
   U-110            32kHz           4           None           6         Tremolo/Chorus           2MB

Audio Outs

How Do I Repair Non‑Working Keys On A U‑20? The U-20 is particularly susceptible to dust particles accumulating on the keyboard contacts. It is recommended you keep the U‑20 under a dust cover when not being used and use a case or a carry bag when transporting it outside the studio. Jim Atwood provides some tips for repairing keyboard problems including PCB repairs, dead key troubleshooting and cleaning key contacts

         U-20 Jim Atwood In Japan
How Do I Test The U‑20 To Make Sure Everything Is Working? [ Warning: Test Mode does a 'Soft Reset'. Backup your internal Patches and RAM Card Patches before testing!! ]

To enter Test Mode
     Press [ PART ] + [ RHYTHM ] simultaneously to enter ROM Play Mode
     While holding [ MARK ] and [ JUMP ], press [ ENTER ] for Test Mode
       * To exit Test Mode, while holding [ MARK ] and [ JUMP ], press [ EXIT ]
  [ JUMP ] + [ BANK 1 ]     LCD Contrast Test (Adjust level by using the Pitch Bender)
  [ JUMP ] + [ BANK 2 ]     LED Test (Adjust speed by using the Pitch Bender)
  [ JUMP ] + [ BANK 3 ]     Internal RAM Test (Also shows the internal battery voltage. Cool!)
  [ JUMP ] + [ BANK 4 ]     RAM Card Test (Also shows the RAM Card battery voltage. Cool x 2!)
  [ JUMP ] + [ BANK 5 ]     PCM Card Test (See Notes)
  [ JUMP ] + [ BANK 6 ]     Internal PCM ROM Test (Outputs letters A - F if OK)
  [ JUMP ] + [ BANK 7 ]     Key + Button + Pedal + PCM Card Insert Tests (DP-2 Pedal)
  [ JUMP ] + [ BANK 8 ]     A/D Converter Test + Visual Aftertouch Tests (See Notes)
  [ JUMP ] + [ NUMBER 1 ]   Control Sliders + External Input Tests (C1, C2, EV-5 Pedal)
  [ JUMP ] + [ NUMBER 2 ]   MIDI I/O test. Connect MIDI IN to MIDI OUT w/cable. Press [ ENTER ]

  a) [ JUMP ] + [ BANK/NUMBER # ] indicates pressing both buttons simultaneously
  b) "PCM Card Test" will only work with PCM Cards SN-U110-11 (in Slot #1) and SN-U110-01 (in Slot #2)
  c) "A/D Converter Test" displays Pitch Bender and Modulation levels when using the Pitch Bender
  d) "Visual Aftertouch Test" shows how lame your U-20's Aftertouch can really be. I was only able
      to get mine up to the 20 - 25 range... nowhere near 127... and I was really pressing hard
  e) See the U-20 Service Notes for detailed descriptions and more test modes
How Are U‑20 Settings Adjusted For The Arpeggiator? Arpeggiator parameters which can be adjusted are
     Type: UP, DOWN, UP & DOWN or RANDOM
     Rate: 0 through 100

To set the Arpeggiator Type;
     Press [ EDIT ] then [ JUMP ] then [ ARPEGGIATOR ]
     Use [ ] CURSOR [ ▻ ] to select Type (blinks)
     Use [ △ ]  VALUE  [ ▽ ] to select UP, DOWN, UP & DOWN or RANDOM
     Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

To set the Arpeggiator Rate;
     Press [ EDIT ] then [ JUMP ] then [ ARPEGGIATOR ]
     Use [ ] CURSOR [ ▻ ] to select Rate (blinks)
     Use [ △ ]  VALUE  [ ▽ ] to select 0 through 100
     Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode
How Do I Turn Active Sensing OFF? By default, the U-20 has Active Sensing turned ON. This sends a MIDI pulse over the wire every 300ms. Personally, I like to turn Active Sensing OFF because the MIDI Message LED's on the rest of my devices start going bat-shit crazy like a strobe light. It's very distracting. I prefer to see MIDI Message LED's trigger only when I play something on the keyboard or when the sequencer is in playback-mode. It also unnecessarily fills up the MIDI buffer and makes troubleshooting more difficult. Sometimes, too many devices on a MIDI chain which have Active Sensing turned ON can cause MIDI buffer overflows and for a couple of seconds, MIDI notes will not reach the module being played. To turn Active Sensing OFF
     Press [ JUMP ] then [ BANK 2 ] then press CURSOR [ ▻ ] five times to select Tx Active Sensing
     Press VALUE  [ ▽ ] and set it to Off

     * This parameter can also be found within the EDIT menu: EDIT/Setup/MIDI/Kybd/TX Active Sensing
What Kind Of DSP Effects Are Built-In To The U‑20 And U‑220? Two basic effects are available: Chorus and Reverb/Delay. The effects routings through MIX OUT are as follows;

   Dry: Part is not affected by the sound patch effect setting
   Rev: Part is only affected by the reverb
   Cho: Part is affected by chorus and reverb
   Dir: Part is sent to the DIRECT OUT jacks

Additionally, when programming the Chorus section, it can be assigned before or after the Reverb section.

Chorus Effects

   Chorus 1: Standard chorus effect
   Chorus 2: Richer and more pronounced effect
   FB-Chorus: Chorus tending towards flanging
   Flanger: As it says
   Short Delay: A chorus with a noticeable delay


Reverb/Delay Effects

   Room 1: Standard room reverb
   Room 2: Slightly bigger room reverb
   Room 3: Warmer room reverb
   Hall 1: Standard hall reverb
   Hall 2: Warmer and bigger hall reverb
   Gate: Weak gate reverb
   Delay: Standard delay
   Cross Delay: Standard left/right delay

(Parameters available for REVERB / DELAY TIME, LEVEL, DELAY FEEDBACK)
How Do I Troubleshoot And Repair The Aftertouch On A U‑20? Aftertouch Troubleshooting And Repair

Non-responsive and lackluster Aftertouch seems to be a complaint from several U‑20 owners. I have two U‑20's. One is really lame when it tries to do Aftertouch and the other one initially did not have any Aftertouch at all. While running the Visual Aftertouch Test, I was only able to get mine up to the 20 - 25 range... nowhere near the maximum of 127... and I was really pressing hard... like the "I might break this key in half", kind of hard. I think the U‑20's Aftertouch problem can be remedied if the contact strips are cleaned. However, the Aftertouch membrane strips are glued in place and it looks like a delicate operation (see below). I've not attempted to remove this glue so the Aftertouch on my U‑20 #1 is still lame. My U‑20 #2 had no Aftertouch at all. That problem was twofold but I was able to fix it

1) The ribbon connector was unplugged, probably from the last owner monkeying around with the keyboard assembly

2) There was a broken solder joint on the Aftertouch ribbon cable connector board at CN2 on the Bender Board Daughter Board. This is also called the Jumper Board [Service Manual P/N: 29-2]). It's a very tiny circuit board only 1cm wide (Figure 1)

After repairing these two issues, the Aftertouch is working again but... it's just as lame as the Aftertouch on my U‑20 #1. This same Jumper Board problem also crops up on the Alpha Juno-2 because it uses a nearly identical miniature circuit board to connect its Aftertouch ribbon cable

(Figure 1)

(Figure 2)

Aftertouch is initiated when a key is pressed down hard which forces two layered membranes together. Depending on how much contact is made between these two membranes will determine the Aftertouch level. I attempted to separate the two layers so I could get inside and wipe off any oxidation on the contacts (Figure 2). However, after about an inch into the removal, I soon realized they were attached together with a strong glue. Why couldn't Roland have used the red epoxy here instead :^)   I decided to stop there for fear of ruining it and have given up on trying to repair the Aftertouch via mechanical means. However, there is one thing to try by way of electronics which might work...

Aftertouch Modification

There is a mod I found in an old U‑20 rec.music.synth post from 1996 (Yipes!) re: an Aftertouch mod. It involves changing resistor values on the Bender Board (R9, R11, R13) and adding a 100k potentiometer for precision adjustment. I'm looking forward to trying this mod someday on my U‑20 #2. My mint condition U‑20 #1 will stay clear of this hack! Instructions for the mod are posted here but I have not tried it out yet so... try it at your own risk
How Do I Repair A Keyboard Suffering From The Dreaded "Red Epoxy Syndrome"? U-20_RED EPOXYThe Problem

The Red Epoxy Syndrome appears on some Roland keyboards manufactured in the late 1980's and early 1990's, including the U‑20*. The red epoxy is used to hold the keyboard weights in place on the underside of each key, white and black. It turns out the epoxy was defective. Over time, the epoxy breaks down, softens and the metal weights fall off. In extreme cases, the red glue seeps down onto the circuit board wreaking havoc. The problem appears to occur more often in warmer climates. It has also been suggested that keeping the synth in a foam padded case will speed up decomposition. The gas released by the foam reacts with the red epoxy. After Roland noticed this defect, later production U‑20's were shipped with keys that had a black epoxy or a specially treated red epoxy as a fix

The Solution

Dissolve the red goop and then reattach the weights using a quality epoxy. Some people have reported good success at dissolving the red goop by using a sodium hydroxide solution (also known as NaOH, Lye or Caustic Soda). However, in a post over at gearsz.com from user XPARIS001, there is a method which costs less than the foul smelling, poisonous and flesh eating sodium hydroxide solution. It's a product called LA’s Totally Awesome All‑Purpose Cleaner. It's non‑toxic and biodegradable. I used this on a full set of U-20 white keys and the results were good. One of the best things is that there's no foul odor and this stuff is only $1 bottle. Not a mis-print. One Dollar A Bottle! I found it at a Dollar Tree store right down the road from me. Bonus!U-20 CLEANER

From my experience with removing the red goop, I suggest you follow these tips
  • When removing the keys from the keyboard bed, write down an ordered list of the numbers which are embossed on each key. The white and black keys all have numbers on them. The numbers are located at the top rear (i.e. CF11, 1-3, D11, 1-1, EB12, CF12, etc...). You will need a list to know the correct sequence when reassembling. I have created an image which shows the correct sequence at this link

  • When removing the keys from the keyboard bed, keep the flat springs in order so you can place them back in the exact location as you found them. Take care not to bend them out of shape. These do not have numbers on them :^(

  • Page 3 of the Roland U‑20 Service Manual has a great step-by-step guide detailing the proper way to remove and replace keys

  • I found the best way to use this cleaner is to pour it over the keys into a pail and cover it with a large plastic bag then seal it with a large rubber band. Although the smell is minimal even without covering it, this step completely eliminates all chemical odors. Everyone in the house will thank you

  • The red goop on my keys was not a drippy liquid but it was not a solid either. I'd say about halfway... like a slightly melted bar of chocolate. I left the keys in the solution for exactly 72 hours. Depending on how solid or liquidy your red goop is, 72 hours may be too long. After 48 hours, all of the goop was dissolved around the sides of the weights and the key could have been washed with water, dried and then have new epoxy applied. I waited longer for the weights to fall out. The weights never did drop out on their own as reported by others who have tried this. I still had to do extra work to remove each weight

  • I only submerged the white keys. The black keys used a different epoxy which was an off-yellow color. It was very solid when poked with a needle and none had any goop problems. 25 less keys to worry about. Yay!

  • Alternate Method Nixed
    • One comment I read online suggested arranging all the keys on a large cookie sheet with the weights facing up. Pour just enough solution in the channel of each key to cover the weight. The advantage of this is that you only need to use a small amount of solution. This method may be better suited for use with sodium hydroxide because I tried it on one key as a test it and it did not work well at all
      • When the red goop started to dissolve, it formed a jello. I kept adding more solution and the jello got thicker and thicker. After 48 hours I just gave up on it because the red goop was not dissolving
      • The playing surfaces of the keys are not cleaned at the same time as compared to submerging
      • Covering the entire cookie sheet to help cut down on the chemical odor is difficult


If you have a low patience level, don't go anywhere near this project. It's a real nightmare. Over my five day ordeal, I used every curse word I know and invented two new ones. On the third day I muttered something out loud like, "...where's the nearest Roland Authorized Service Center?" and also checked eBay for any new U‑20 auctions. If you decide to do this refurb, the method I would choose is LA’s Totally Awesome All‑Purpose Cleaner as opposed to the sodium hydroxide method. I was a little disappointed that the weights did not fall off on their own. It caused some extra work but my goal was accomplished. I think that if your red goop problem is in a liquidy state, the weights will drop off just fine. I think the glue on my keys was harder than most

* Keyboards with the red goop problem are EP‑9, JD‑800, JV‑50, JV‑80, JV‑90, JV‑1000, U-20, XP‑80, XP‑90, D‑70 and VK‑1000. I'll bet the Roland Customer Service Department shit a brick when these keyboards started failing at the same time all over the world :^)

An Error Message On my U‑20 LCD Says "Key Scanner Error". How Do I Fix That Problem? No clue :^(

A visitor to this website had a U‑20 with this error. He took it to an Roland Authorized Service Center and they reported it was unrepairable
Who Is Crazy Enough To Remove A Version 2.00 Main Circuit Board From A Working U‑20 And Replace It With A Version 3.03 Circuit Board? That would be me. The crazy one. I found a good deal on eBay for a Main Circuit Board with the Version 3.03 ROM IC soldered in. Since my spare U‑20 was running with an old Version 2.00 ROM (also soldered in), I wanted to see if I could swap them. Both boards were identical with the exception of ROM IC#8 and both boards had the same part numbers (U‑20 ASSY   |   76213900   |   292‑735‑01). I had great results but there were a few minor roadblocks along the way. If you decide to do this upgrade, be aware of these issues
  • Some of the cable hookups use Wire Trap Connectors (Figure 1). I never worked with these before. I was unable to figure out how they worked until I posted a question online. Someone in the Synthesizer Spares or Repair Facebook group showed me how they work. After you know the secret, it's easy. Your first inclination is to pry up the top of the connector and pull the ribbon wire out. Don't! The ribbon wire is locked in place (Figure 2). You need to take a flat blade screwdriver and push down on the connector. This basically "unlocks" the ribbon wire from the connector making it easy to pull up and out (Figure 3)

  • Remove the 3V battery before you swap the boards. Install the battery after all of the board cables are plugged in

  • There are plenty of ways to disable a U‑20. This could be one of them. This is a very risky and time consuming project. Especially risky are the wire trap connectors and cables. These cables are flimsy and after a few connects and disconnects, the wires start to bend and fray. They seem best suited for a one‑time use when they were first assembled at the factory. After a few weeks of use, I haven't noticed any compatibility issues between the v3.03 Main PCB and the other PCB's which were not changed out and previously connected to the v2.00 Main PCB (i.e. Switch Board Left, Switch Board Right, Bender Board, etc...). I'm not posting any instructions here because if you attempt this, you are obviously mechanically inclined enough to figure things out on your own. I'm posting this just to let others know it can be done if needed

Where Can I Get U‑20 Questions Answered? A popular online forum for getting a lot of synthesizer related questions answered is at gearsz.com;

         SUPER JX http://gearsz.com

* * * ROM IC VERSIONS * * *
To determine the ROM IC version

   [ Warning: Checking the ROM IC version does a 'Soft Reset'. Backup your internal Patches first!! ]

     In the PLAY MODE section, press [ PART ] and [ RHYTHM ] simultaneously, to enter ROM PLAY
     While holding [ MARK ] and [ JUMP ], press [ ENTER ]
       * To exit, while holding [ MARK ] and [ JUMP ], press [ EXIT ]
28-Pin MASK ROM v2.00 For The U-20

     Press [ DATA ] then use the [ ] [ ▻ ] buttons to select UTIL, press [ ENTER ]
     Use the [ ] [ ▻ ] buttons to select ROM PLAY, press [ ENTER ]
     While holding [ MARK ] and [ JUMP ], press [ ENTER ]
       * To exit, while holding [ MARK ] and [ JUMP ], press [ EXIT ]

     Turn the power on while holding the [ DEC ] and [ INC ] buttons
     * To exit, press [ DEC ] + [ INC ] simultaneously to cycle through the remaining test screens

I was very surprised to find that my U‑20 ROM IC was soldered directly onto the PCB and not socketed. Yipes!!! This change by Roland was made to cut production costs which was a horrible decision for techno geeks like myself who like to make backups of synth firmware and help other synth owners upgrade to the latest and greatest version. I've discovered that the ROM installed on most U‑20's are not EPROM's but are instead MASK ROM's and you can't copy the binary code and burn it onto an EPROM

The Good News:
If your U‑20 has a MASK ROM, the electron data will not deteriorate over time like that of a regular EPROM

The Bad News:
If your U‑20 firmware is v1.x or v2.x, upgrading your firmware is nearly impossible

ANIMATED_STAR Detailed info, old forum posts and ideas re: U‑20 MASK ROM upgrades can be found at this page ANIMATED_STAR


IC8 on the PCB
VER. 1.03     [ 89/05/16 ]
VER. 2.00(a)  [ 89/06/16 ]
VER. 2.00(b)  [ 89/08/04 ]
VER. 3.01     [ 89/xx/xx ]
VER. 3.03(a)  [ 89/10/30 ]
VER. 3.03(b)* [ 89/12/22 ]
* Final ROM IC Version


- ROM IC Version - Visual ID

- - - - VER. 2.00(a) - - - -

V2.00 8931D

- - - - VER. 3.03(a) - - - -

VER 1.03 ROM IC Fixes These Bugs

VER 2.00 ROM IC Fixes These Bugs
1) Problem with DSP Effects IC initialization corrected (almost). Spurious noise or no sound at all is noticed at times when you select Patch I-88 (v1.03 ROM)
2) Rhythm Part did not change level when MIDI Volume was received
3) Key Range settings were non-inclusive (v1.03 ROM)
4) Key Velocity ranges were set with Min and Max values (v1.03 ROM). This is changed to Offset (lowest value setting) and Sensitivity (how steeply the velocity will rise) with the v2.00 ROM

VER 3.01 ROM IC Fixes These Bugs

VER 3.03 ROM IC Fixes These Bugs
1) MIDI times are more responsive
2) The following new parameters have been added
    • Rx Volume, Rx Pan and Rx Hold can be set ON/OFF for each part
    • Level Boost for Rhythm Part
3) Buffer overflow may occur when receiving MIDI SysEx
4) Problems with DSP Effects IC initialization. The Service Notes say it "seldom happens" ;^)
5) Parts 1 through 6 won't always recognize Poly Aftertouch
6) When a Tone is using two voices (as in "Velocity Mix" or "Detune") and it is assigned to "Rhythm Part", the level of the two voices will get unbalanced
7) When a voice in a Rhythm Part has stopped sounding, it is not released from the part
8) Volume Level 0 is not silent


IC8 on the PCB
VER. 1.00      [ 88/xx/xx ]
VER. 1.01      [ 89/12/25 ]
VER. 1.02*     [ 90/02/16 ]
* Final ROM IC Version

Burn your own U‑220 ROM here
VER 1.01 ROM IC Fixes These Bugs
1) Modified the demo song
2) Fixed a bug with velocity on the acoustic and electric piano tones


IC#? on the PCB
VER. 1.00      [ 88/xx/xx ]
VER. 2.03*     [ 88/xx/xx ]
* Final ROM IC Version Unknown
VER 2.03 ROM IC Fixes These Bugs

* * * SPECS * * *
U‑20 38 3/4" (985 mm) 12 1/16" (310 mm) 3 1/4" (85 mm) 22 lb.  (10 kg)
U‑220 19" (482 mm) 14 1/8" (358 mm) 1" 3/4 (45 mm) 9 lb. 11 oz.  (4.4 kg)
U‑110 19" (482 mm) 14 1/8" (358 mm) 1" 3/4 (45 mm) 9 lb. 15 oz. (4.5 kg)
U‑20 20W 30 Arpeggiator / Control Change Sliders (C1 + C2) / RAM Data Card Slot
U‑220 20W 30 4 Audio Outs
U‑110 21W 31 6 Audio Outs / 4 PCM Card Slots / Tremolo+Chorus DSP
U‑20 1989 $1,695 USD 128 PCM Waveforms 64 Patches / 128 Timbres / 8 Chord Sets / 4 Rhythm Sets
U‑220 1989 $1,095 USD 128 PCM Waveforms 64 Patches / 128 Timbres / 4 Rhythm Sets
U‑110 1988 $1,095 USD 128 PCM Waveforms 64 Patches / 99 Timbres / 1 Rhythm Set
P/N: CR2032 **       SUPER JX Battery Replacement DIY       CR2032 Battery
High Quality Replacement Power Switch [ U-20 Only ]
Power Rating: 6A @ 250V AC

Type: SPST w/Solder Lugs

Panel Opening: 13mm x 19mm
P/N @ mouser.com 633-CWSA11AANS* 633-CWSA11AAN1S 633-CWSA11AAN2S 633-CWSA11AAN3S
* The original 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 Alpha Juno-1/2 case, the lettering is upside‑down. Every U‑20, JX‑10 and Alpha Juno‑1/2 I've ever seen is the same way as shown here

The replacement switch most similar to the original is Mouser P/N: 633‑CWSA11AANS but it does not have the red bar so... it's even worse than the original!! 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 more visibility. The price for P/N: 633‑CWSA11AAN1S as of March 2016 was $1.80 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 Super JX‑10, JX‑8P, Alpha Juno‑1/2, Juno 60/106, JV‑80, JD‑800, D‑10/20/50/70, MK‑80, and MPU‑101
Average Quality Replacement Power Switch [ U-20 Only ]
Power Rating: 6A @ 250V AC

Type: DPST w/Solder Lugs

Panel Opening: 13mm x 19mm
SKU# @ taydaelectronics.com A-5091 A-5092
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 March 2016 was only 25¢. After evaluating all types, I prefer the higher quality switches from Mouser
Replacement Power Switch [ U‑220 Only ]
Power Rating: 5A @ 250V AC

Type: ON/OFF w/Four Solder Lugs
P/N: ALPS: SDGA3P           Sony/JVC/Panasonic: 554-880-12           Roland: 13129124
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 U‑220 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‑70, MKS‑80, MKS‑100, S‑220 and S‑550. 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 than $11 (USD). Do a keyword search for "ALPS  SDGA3P"

* * * ACCESSORIES * * *
SN-U110 PCM Expansion CardsPCM Card

The two slots labeled "PCM CARD" on the back of the U-20 is for use with SN-U110 PCM Cards. There are a total of 15 PCM Cards available from Roland which are used to expand the sound capabilities. These cards also work with the U‑220, U‑110 and D‑70. It is important to note that two of those cards "SN‑U110‑08 Synthesizer" and "SN‑U110‑09 Guitar & Keyboards" are already hard‑coded on a ROM IC inside the U‑20, U‑220 and D‑70 so don't waste your money buying those unless it's for a U‑110. Also, be aware that "SN‑U110‑10 Rock Drums" is not compatible with the D‑70. With the exception of a few cards, I have heard almost all of the PCM samples and the top three cards which impressed me the most are (in order);

      1. SN‑U110‑12 - Sax & Trombone
         (I'm totally bonkers about this card. Some of the most realistic samples I've ever heard)

      2. SN‑U110‑03 - Ethnic
         (A great selection of Sitars, Tablas, Balafons and more. Note: Roland has misspelled Balafon as Baraphon)

      3. SN‑U110‑07 - Electric Guitar
         (Wayne's World! Wayne's World! Party Time! Excellent!)

A great reference site for SN‑U110 PCM Cards is available at BigRedRoo

PCM Card

Some doofus on eBay is selling reproduction printouts of the SN‑U110 Sound Charts at $10 per card. Forget that shit! Roland Japan has them posted online in the Support section and you can download them for free. High‑resolution scans of the original Sound Charts in one handy PDF file here

To access the sounds of a PCM Sound Library Card plugged into a U-20;
     Press [ JUMP ] [ NUMBER 2 ] and the LCD Display shows
       Tone = (x)-(yyy)  (zzzzzzzzzz)
                x = PCM Card Number. For example, "SN-U110-11 Sound Effects" is PCM Card #11
              yyy = Tone Number on the PCM Card. For example, 004
       zzzzzzzzzz = Tone Name on the PCM Card. For example, WATERPHONE 

Use the      cursor to select x and it will start blinking
Press [ △ ]  VALUE  [ ] until one of the PCM Card Numbers (x) appears and starts blinking
Use the [ ▻ ]  CURSOR to select the Tone Number on the PCM Card (yyy) and it will start blinking
Press [ △ ]  VALUE  [ ] to cycle through the available Tone Numbers (yyy) and Tone Names (zzzzzzzzzz) on the PCM card

    Note: To speed up this process, instead of using [ △ ]  VALUE  [ ], you can use the C2 Slider to cycle through the Tone names

For our example of using the SN-U110-11 Sound Effects PCM Card, the LCD display will read as;

       Tone = 11-004  WATERPHONE
               11 = The PCM Card Number (SN-U110-11 Sound Effects)
              004 = The Tone Number on the PCM Card
       WATERPHONE = The name of the Tone on the PCM Card
If the LCD display looks something similar to what is shown below and says "No Card!", you will need to change (x) to match up with the PCM Card number(s)
       Tone = (x)-(yyy)  No Card!
PCM Card    PCM Card    PCM Card    PCM Card
Card Images Courtesy Of BigRedRoo

PCM Card Slots
PCM Memory Cards

The slot labeled "RAM CARD" on the back of the U‑20 is for use with Roland Memory Cards M‑256(D/E/G) and M‑512(D/E/G). These PCM RAM Cards allow storage for an additional 64 Patches and 128 Tones. Both cards will work exactly the same. However, using an M‑512 RAM Card is overkill because the extra memory on the card is not accessed. The U‑20 was originally designed to work with the M‑256 RAM Card... before the larger M‑512 RAM Card was manufactured

When inserting a PCM RAM Card for the first time or if the card contains data from a different model synthesizer, a message will appear on the LCD Display;
   It's a New RAM Card.
   Initialize it? [ENTER]
After initializing the RAM Card, "Function Complete." will appear on the LCD Display. All of the U‑20's internal Patches and Tones are automatically copied onto the RAM Card immediately after initialization

To access Patches on the RAM Card, press [ CARD/B ] [ BANK 1-8 ] [ NUMBER 1-8 ]

To save all internal Patches to the RAM Card
        Press [ JUMP ] [ EXIT ]
        Use [ ] CURSOR [ ▻ ] then [ △ ]  VALUE  [ ] to select "All"
        Use [ ] CURSOR [ ▻ ] then [ △ ]  VALUE  [ ] to select "Int →Card"
        Press [ ENTER ]
        Press [ △ ]  VALUE  to confirm

        Alternatively you could
             Select "Int← Card" to load all the RAM Card Patches into the U‑20's internal memory
             Select "Int←→Card" to exchange all the RAM Card Patches will all the Patches in the U‑20's internal memory

A visitor to the GR‑1 Homepage passed along some very useful info about troubleshooting a once working 256 RAM Card. Thanks for the info, Al! The problem was the error message "NOT GR1" would display but the system would not allow the card to be formatted. The solution was to perform a Full Copy (Dump) of the patches to the card. When the message "FORMAT?" is displayed, press "YES". The "COPY COMPLETED" message will appear. You can now read and write to the card. The standard "FORMAT" option only works for brand new un‑formated and un‑corrupted cards. If you are experiencing 256 RAM Card or 512 RAM Card problems on your U‑20, similar actions might be the solution

When inserting or removing cards from the "RAM CARD" slot, always make sure the switch on top of the card is set to the PROTECT position to prevent accidental erasure of any data. These cards use an internal lithium coin cell battery which the owner's manual says to replace every 2 years. However, I have found my battery lasting anywhere from 5 to 7 years. The replacement battery is P/N: CR2016

         U-20 Homepage M-512E Owner's Manual (Japanese / French / German / English)
PCM CardPCM CardPCM Data Slot


This foot pedal is a variable resistor for controlling different parameter functions. Depending on how the EXT CONTROL jack is assigned for individual Patches, this pedal can modify MIDI Control Changes in real‑time. The EV‑7 and EV‑10 expression pedals are identical to the EV‑5 except they are housed in a metal case, not plastic. The EV‑10 had an extremely brief production run before it was replaced by the EV‑5. Recently, the EV‑7 seems to have been removed from the inventory of most online retailers

One example of using an expression pedal to control a Patch is as follows;
          Choose Patch I-46 Synth Bass 5
          Press [ JUMP ]  [ BANK 4 ]
          Press [ ▻ ] CURSOR 5 times
          Change the LCD Display to read "EXT:Ch Tx=Ch Ext   #10"
          Now whenever the expression pedal is moved up or down, the sound will pan left to right or right to left
          The #10 setting is the Control Change parameter for Panning. Real‑time MIDI data is also sent
          Other Control Change parameters can be set as well
               #1 = Modulation          #7 = Part Level          #64 = Sustain

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! Granted, it's not a true foot controller but, it's still a useful real‑time input device


❖ Also works great with the Synthrotek MST Expressor Eurorack module
❖ 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
❖ 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)

U-20 Homepage EV-5 Owner's Manual
   (Japanese and English)
  EV-5 DIY Parts List (Hand Controller Version)
   Tayda P/N: A-1982 - 10K Ohm Linear Pot
   Tayda P/N: A-1983 - 50K Ohm Linear Pot
   Tayda P/N: A-5081 - 1/4" Stereo Plug
   Tayda P/N: A-5166 - 1590A Enclosure
   2-Conductor Shielded Cable (Shield = Ground)


Variation: DIY Dual hand controller with optional output jacks

Adjusting the EV-5 Minimum Volume Knob
DP-6 PEDAL [ Momentary Switch For Hold Control / Patch Change ]
DP-8 / DP-10 PEDAL [ Momentary Switch For Hold Control / Patch Change + On/Off Switch ]

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 (located on the side of the DP‑8 / DP‑10) to the "Switch" position.

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. 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 function. 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 the half‑damper capability of your keyboard

Switch Control: Set the select switch to the Switch position to use the pedal as an on/off switch


U-20 Homepage DP-8 Owner's Manual
DP-2 PEDAL [ Momentary Switch For Hold Control / Patch Change ]

Same function as the DP‑6 pedal but the DP‑2 model costs less and is made mostly of plastic parts
FS-1 [ Patch Change - On/Off Switch]

This is an ON/OFF switch and is made mostly of metal parts
Pedal Model     Description            Product Status
-----------     ------------------     --------------
   FS-1         On/Off                 Discontinued
   DP-2         Momentary              Current
   DP-6         Momentary              Discontinued
   DP-8         Momentary + On/Off     Discontinued
   DP-10        Momentary + On/Off     Current
   EV-5         Variable Resistor      Current
   EV-7         Variable Resistor      Current
   EV-10        Variable Resistor      Discontinued

* * * ERROR MESSAGES * * *
  Internal Battery Low!!       
  The internal battery has died U-20 Battery Replacement Guide
  Checking PCM Card . . .
  When you insert or remove a PCM card, this message will appear and operation will briefly halt. (This is normal)
  It's a New RAM Card.
Initialize it? [ ENTER ] 
  The RAM card inserted into the RAM card slot has not been initialized for use by the U-20

  Action 1:
  If the RAM card is new or if you want to use a RAM card from another device for the U‑20, press [ ENTER ]
  The RAM card will be initialized, and internal memory data will be written into it. Use only M‑256 or M‑512 RAM cards
  Action 2:
  If you have mistakenly inserted the wrong card, remove it immediately

   See the Troubleshooting Section if you experiencing problems during format MKS-50 PCM Memory Cards
RAM Card Protected
  The protect switch of the RAM card is On, and writing is not possible
  Turn the protect switch of the RAM card OFF, and try the operation again
    Card Not Ready

    RAM Card Verify Error!
  When writing, saving or loading, the data was not correctly written into the RAM card
  Make sure that the RAM card is correctly inserted, and try the operation again
  RAM Card Battery Low!
  The battery of the RAM card has run down
  Replace the battery according to the instructions in the RAM card manual
  Illegal PCM Card! 
Please, take it out.
  The card inserted into the PCM card slot is not a PCM card
  Immediately remove the card from the PCM card slot
  Receiving Exclusive.
  Exclusive data is being received. Wait until reception ends
  (If the exclusive data being received is very short, this message will not appear)
  Transmitting Exclusive.
  Exclusive data is being transmitted
  When transmission ends, the display will show "Function Complete", and then return to the previous display
  (If the exclusive data being transmitted is very short, this message will not appear)
  SysEx Check Sum Error!

  SysEx Data Length Error! 
  System exclusive data was incorrectly received
  Check MIDI cables and the message that was transmitted, and try the operation again
  Sure? [ VALUE Δ ] / [ EXIT ] 
  This message will always be displayed when you write data into internal memory or a RAM card   If you are sure you want to write the data into memory, press [ VALUE Δ ]
  To quit without writing data into memory, press [ EXIT ]
    Function Complete. 
  The write, save, or load operation has been completed
  Wait for a short time until the previous display appears
  MIDI Buffer Full ! 
  If this error is shown while using a SysEx load/save program, the MIDI send and receive settings on the computer are too fast for the U‑20 MIDI buffer. Try setting the MIDI buffer size in your SysEx program to a smaller value

  If this error is shown while communicating with another MIDI device such as an external keyboard or sequencer, too many Program Change or Control Change messages are being sent to the U‑20 and overloading the MIDI buffer. Try setting Rx SysEx = OFF
          Press [ JUMP ]  [ BANK 1 ]
          Press [ ▻ ] CURSOR three times
          Press [ ]  VALUE  to select Rx SysEx = OFF
          Press [ KEYBOARD ] + [ SOUND ] at the same time to resume normal play mode

Who Dat?
Who Created The U‑20 Homepage And Why?

The very first merit badge I earned in the Cub Scouts was for creating complex patches on the ARP 2600. Ten years later, I discovered the electric guitar and traded my Cub Scout uniform for a bong. Ten years after that, I was playing experimental electronic music with the band LLAMA and used the U‑20 as my main keyboard controller... I'm still using the U‑20 as my main keyboard controller. I love the sound of the U‑20 and wanted to create a webpage resource where everything about this great synth is freely available to everyone

The keyboard player for Nine Inch Nails (James Woolley) borrowed my U‑20 for a session in 1992. In retrospect, I should have had him autograph it DOWNER

Other Synthesizer Homepages I Maintain


PROMO WEBSITES     PROMO WEBSITES     The Andromeda Strain - Best Movie Ever!


U-20 ZONE     U-20 ZONE U-20 ZONE - BATTERY U-20 ZONE     U-20 ZONE