• Fast, dense chords are played
• Large amounts of streaming MIDI data fill up the U-20's MIDI buffer
  
• The setting Rx SysEx = ON

• The U-220 and U-110 are unable to use M-256E or M-512E RAM 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

  [ 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 ]

  Notes:
  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

• 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
  
  
• An online visitor has discovered that leaving the pail of solution and keys in the sun all day will actually speed up the dissolve process. His weights were dropping out by mid‑afternoon
  
  
• 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 red goop problems. 25 less keys to worry about. Yay!
  
  
• When reattaching the weights, I recommend using Loctite Epoxy Instant Mix™ (UPC: 079340686205). Only mix enough for 10 weights at a time or it will harden too quickly. You don't need to completely surround the weight with the epoxy as Roland did. They used a weaker epoxy (obviously!) and thus had to overspread it. Using a toothpick to apply two small "pencil eraser sized" dabs at the front and back will work fine (see image). This is extremely strong stuff and perfect for gripping something like keys which see a lot of action. In the event you didn't notice when you removed the weights, the four dimples face inward and touch the key. My guess is these were designed to keep a small gap in‑between the weight and the key to increase the height of the epoxy layer for a stronger bond. Warning: Don't get any of this shit on your fingers or on top of the keys. Even when unmixed, the liquid components in the Loctite Expoxy are unforgiving. From experience, I always use latex gloves when using this stuff. No matter how hard you try to keep clean, you will always end up getting some on your fingers
  
  
• 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
      
      

• 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 use your fingers or a small flat‑blade screwdriver and push down on the side of the connector (Figure 3). This "unlocks" the ribbon wire from the connector making it easy to pull up and out
  
  
• 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
  
  

  

       Edit/Timbre[1]/Tone
       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;

       Edit/Timbre[1]/Tone
       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

       Edit/Timbre[1]/Tone
       Tone = (x)-(yyy)  No Card!

            
Card Images Courtesy Of BigRedRoo

   It's a New RAM Card.
   Initialize it? [ENTER]

EV-5 / EV-7 EXPRESSION PEDAL

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

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

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

  Internal Battery Low!!       

  Checking PCM Card . . .

  It's a New RAM Card.
  Initialize it? [ ENTER ] 

  Data/***** 
    RAM Card Protected

  Data/*****
    Card Not Ready

  Data/*****
    RAM Card Verify Error!

  RAM Card Battery Low!

  Illegal PCM Card! 
  Please, take it out.

  Receiving Exclusive.

  Transmitting Exclusive.

  SysEx Check Sum Error!

  SysEx Data Length Error! 

  Data/***** 
  Sure? [ VALUE Δ ] / [ EXIT ] 

  Data/***** 
    Function Complete. 

  MIDI Buffer Full !