Roland U-20 Synthesizer Key Contact Repair

Roland U-20 RS/PCM Synthesizer
Roland U-20 RS/PCM Synthesizer

Yesterday, I was given a Roland U-20 by one of the sales clerks at a local Hard Off store here in Japan. Only one key was working and rather than just selling it as junk, he decided to just throw into the bag along with my guitar strings that I purchased…laugh. I told the guy that it was a very common problem with the Roland U-20 that the keys were bad so perhaps I might be able to find more info and try to fix it. He said “Good Luck” and I was off on another project. With the success a day earlier with the Yamaha SY77 in my previous post, I was looking forward to the Roland U-20 challenge. This article talks about some things that did not work and some repair methods that worked 100% in fixing the key issue. Below are some points to remember about the Roland U-20 problems.

1. The Roland U-20 is a easy, but time consuming to take apart. You pretty much have to unscrew everything and move the PCB boards out of the way in order to get the keys out of the U-20. It’s very simple to do, but a pain to have to remove everything. I actually just removed the screws and shifted them around to make clearance so that I could slide the key assembly around. The components, especially the ribbon cables are delicate so be careful and take your time.

2. There is a flimsy ribbon cable attached to the key assembly ( see photo below ) which I did not remove. I’ve heard one shouldn’t remove this cable because it “could” result in the removal of some of the traces. If that happens, it’s easy to repair, but I found that I didn’t need to remove the cable. Instead I removed the key assembly and while balancing it in one hand, I reached over and placed the metal bottom cover back on. I then carefully placed the key assembly on a work towel on top. The ribbon cable is just long enough to rest the keys on the bottom of the synth to work from. The reason for doing this was so that I could test each key with the power on when ready. There was NO WAY I was going to put all this back together only to find out one key didn’t work. The keys were going to work perfectly before I reassembled the U-20 and so it was paramount that I could test the keys during my repair. Resting the key assembly on the bottom of the synth meant I could cover the PSU and not worry about bumping any of the other components during the repair process. I worked with the power off until I was ready to test the Silicon rubber contacts.

Roland U-20 Synthesizer
Ribbon Cable Roland U-20

3. The Roland U-20 also has the dreadful red epoxy problem. You can see in the photo that the epoxy is already starting to break down. Usually I soak and wash the keys in a special solution that removes the red epoxy. This can take several days, so for a quick fix that works well, I simply apply some rubber goop cement that actually acts as a sealant to prevent the red epoxy from escaping. Since the epoxy is at it’s earliest stages of breaking down, I found the quick fix to be enough to cure the problem. Now if the weights were falling off and the keys were sticking together, I of course would opt for the full cleaning workout.

Roland U-20 Synthesizer
Red Epoxy Roland U-20

4. The Roland U-20 suffers from the reduction and/or obstruction of the carbon Conductive contacts/prints on the PCB board and Silicone Rubber pieces. In the photo below, I used a product called Caikote 44 which allowed me to apply a thin Conductive Silver/Carbon Coating over both the Silicone Rubber contact AND the carbon print contacts on the PCB board. IMPORTANT!!! In the photo you will notice I did a rather messy job of applying the conductive coating onto the PCB board carbon prints. This is WRONG! I had a “DUH” moment and realized that you MUST apply the conductive coating on each individual carbon contact without touching the others. I later went back with some alcohol solution and removed the excess in between the contacts. Each key has 3 or 4 individual carbon prints to coat.

Some people just clean these with alcohol cleaner and put the key assembly back together. I find this didn’t work at all for me and I felt it was a bit unreliable as well or at least could be. Instead I found with past experience that on the Korg PolySix, Caikote 44 was THE BEST solution for cleaning this annoying problem without ever having to think about it again. This is laughingly why I caked the stuff on the first time because boy it works wonders. My Polysix has been playing beautifully ever since I slapped that Conductive Silver/Carbon Coating on it. I can tell you it works awesome for the Roland U-20 as well. Note, you may need to use a toothpick or something thin in order to apply effectively. When I tested the keys with the slop job I did above, none of the keys worked. I then knew I was suppose to apply the Conductive Silver/Carbon Coating to each contact individually. This makes sense and I don’t know why I did it the messy way…laugh. Actually I’m being hard on myself in that I really wasn’t sure, so I suppose I now have the experience of knowing otherwise.

Roland U-20 Synthesizer
Conductive Silver/Carbon Coating Caikote 44 Roland U-20

After putting the Roland U-20 back together, everything works perfectly. It simply sounds great and all of the keys work 100% as they should. I can also rest assured that with the application of the Conductive Silver/Carbon Coating, I won’t be waking up on a cold morning to discover one key is now dead. It should continue working “hopefully” for years to come. I will say again though as I’ve said it in past articles. You really need to keep playing these synthesizers to keep them in shape. Letting them sit for years on end will not keep them in good “working” condition. They need to be played, especially synths with key issues.

The Roland U-20 is a fun little synth. It has some great sounds on board that don’t seem to exist in later Roland models such as the JV-1080. Some of the Roland U-20 sounds are pretty unique. Furthermore, the U-20 has TWO programmable chord memory buttons instead of one that many other synths have. This allows for some creative playing which I enjoy. There is also an arpeggiator that can also be applied to the chord memories. Plus there are a couple of assignable slider controls. The U-20 has six parts and an additional rhythm part for external sequencing. There is a transpose button, joystick with modulation, and jump button for easier editing of sounds. It’s about the size of a Nord Lead and it’s very light weight. The keys actually feel pretty good once you have them in shape. Mine don’t clack or trip my fingers up at all. There are some classic sounds on board and the effects sound wonderful too. Yes it’s old, dated, and limited a little bit, but it definitely has a bundle of character. Yes, it’s a rompler but the kind I don’t mind having at all. It will do the job just fine.

10 thoughts on “Roland U-20 Synthesizer Key Contact Repair

  1. Jorick

    Hi Jim,

    I currently own 2 U-20’s. Although they are very basic synthesizers they look great, sound great and I like the action of the keys.

    Bought the first one a couple of years ago. Only 5 or 6 keys worked. Took it apart and cleaned all the contacts. It’s been working fine ever since! I only use it once in a while and the first couple of times I was always afraid half the keys would be dead when I powered it on after not using it for three months.. but it’s been working fine for years now.

    Last week I bought a second one for almost nothing and I was just testing it for the first time 20 mins ago. 🙂 Only three dead keys and a couple of buttons that don’t work. Ran it through the selftest pages and found no further problems exept the aftertouch. Even when I press a key REALLY hard I only get a value of like 20. This is also a common problem for the U-20 (and some other Rolands) Just for the fun of it I am going to try and fix this. I believe it involves soldering in a resistor somewhere.

    About the flatcable: indeed, never disconnect at the keybed side. But you can easily disconnect it at the mainboard side. I recently repaired a D-70 where the flatcable came loose from the keybed side (common problem) and you say repairing that is easy? After a few experiments with conductive silver glue I ended up cancelling the flatcable alltogether and glueing 16 seperate wires onto the damaged traces and soldering those wires to the PCB on the other side. Not for the fainthearted 🙂 I thought it would never work again but when I powered it on, tested all the keys and found them all working again I was very happy. I used ‘Wire Glue’ to glue the wires onto to traces. It’s a black conductive carbon glue and it’s pretty ‘thick’. That makes it very easy to work with as the L100 conductive silver glue is watery thin and runs very easily connecting all the traces..

    I always source my project synths of the internet. I need to find a local store that gives me these things for free like you have 😀 *jealous*

  2. Sören Ahrens

    Hi Jim, my U-20 from Roland has got a Problem. only one key on the internal Keyboard ist playing, the right one is working, not the Rest
    Via Midi i can get every sound on my E-Piano.
    I have no idea .
    I want to play on both Keyboards .

    Can you help me. Excuse my bad English ,

    Dear Sören

    1. Hi Sören,

      What do you mean when you can get every sound on your e-piano?

      Only 1 key is working on your U-20? If you midi another keyboard (the e-piano?) to the U-20 and you play the e-piano everything works fine? -> break out the screwdrivers because your U-20 needs maintenance.


      When you midi the U-20 to the e-piano and you play the U-20 everything is fine? This would be strange though reading your description of the problem..

      grtz, Jorick

  3. Peter Spencer


    I read about not removing the ribbon cable from the keyboard until after the fact. Great! You mentioned that the ribbon cable was “easily” repairable. How? Any help would be greatly appreciated.


  4. Hi Peter,

    If you’ve disconnected the ribboncable at the keyboard side you have a problem. If all 16 traces still look good on the green pcb and the silver cable you can try putting it back together. You can replace the transparent plastic strip and the two black pins keeping it in place by a slightly curved metal strip and two nuts and bolts to keep pressure on the connection. If this does not work you can also try this:

    grtz, Jorick

  5. Jean-Paul Tourigny

    Hi Jim! I have a Roland EP-7 that came to me with the four highest notes being dead (E, F, F#, G). After some investigation, I concluded that the (flimsy) ribbon connection was likely the culprit. You guessed it, the connector is now separated from the green PCB on the 20 connection side of the key bed. Can you please let me know whether there is now an easy affordable solution other than hard-wiring from the PCB as was done on a D-70 keyboard. Regards, JP

  6. George

    Just perfect! Thank you very much for your support in this case! I really needed this information about Roland U-20 , because I had the same problem too. Regards!

  7. I’m going to see if I can talk my husband into trying this. I have one U20 on a shelf that quit working years ago – and this article was not around. And now, a newer U20 is suffering the same symptoms. Could I please ask, is your U20 still working? (I’m wondering if it is worth the time involved if we get the product mentioned above to help the contacts.) My husband took the first one apart years ago and, as you know, it is not easy. We didn’t know about Caikote 44 then, and it didn’t work for long. Just wanted to see if your U20 still plays. Thank you. Lisa

    1. Hi Lisa,

      I have repaired my U-20 five years ago and it still works fine. I’ve recently played it after it was in storage for about half a year and everything still worked oke. I didn’t use Caikote on the contacts.. just cleaning alcohol and q-tips.

      Regards, Jorick

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