so I have this very old Casio CTK-471 keyboard lying around, so I thought I'd make a midi controller out of it. I bought one of those cheap Viewcon USB-MIDI interfaces and it seems to work because whenever I press a key or receive signal from the computer, the interface lights a led up. Problem is many of the keys don't actually play any sound on the PC, some play 2 different notes, and some aren't even in order.

This issue has been driving me mad for weeks, what could I do? There are no Casio drivers I could find for this old model. Also, the keyboard has no problems playing without MIDI, it's just the MIDI signal that gets lost somewhere along the way.

  • I don’t think I’d be able to help, but it might make it easier for someone to help you if you explain what you’re connecting the keyboard to. I’m guessing it’s a computer, but it would still help to know what software you’re trying to send MIDI info to. Aug 13, 2018 at 0:39
  • I did a similar thing with organ pedals, which involved only 13 wires connected to a board that converted to MIDI. So long ago, things have probably moved on. But it works!
    – Tim
    Aug 13, 2018 at 7:07
  • My keyboard has MIDI IN and MIDI OUT ports, I bought a cheap MIDI to USB interface and I am using that to connect my keyboard to the PC.
    – Press Play
    Aug 13, 2018 at 11:29
  • "Problem is many of the keys don't actually play any sound on the PC" ... Using what software?
    – Yorik
    Aug 14, 2018 at 15:47
  • Since I don't actually have any professional software, I was just using MIDI-OX and multiplayer piano.
    – Press Play
    Aug 14, 2018 at 18:41

5 Answers 5


The cheap generic Midi device with the violin clef on it is renowned for causing troubles (it's not necessarily just those: I had a "Swissonic" looking differently with similar problems). Among the reported troubles are dropped key presses and releases for chords and garbled SysEx messages.

Now for single key presses there should not likely be an immediately apparent problem: this is more to be expected when multiple keys are combined by the keyboard (like when using some chord-generating automatism) and thus occur in very tight succession. It may also be that the interface gets confused by 0 velocity key presses (sometimes used instead of key releases to save one byte of transmission). The use of the respective cheap chip may also occur with a lacklustre interest in wiring standards. My own cheap Chinese interface also messed up ground separation and thus caused a ground loop. And the complete optical isolation of the connection is basically the main thing that has kept a 31250bps (which is what optocouplers are comfortable with) standard alive for all those decades. Ground loops can also affect the reliability of the MIDI connection as well as mess up analog connections.

So your first step would be getting a MIDI interface of a somewhat renowned manufacturer. You'll need it at some time anyway, and "Full Speed" USB1.1 at 12Mbps will go a long way before you are getting into jitter or even contention problems, so it's not like you need to break for the latest and newest.

Once you have a solid interface, your experiments will actually mean something. Then it will be somewhat possible to figure out whether or not that keyboard will work for your purposes, or whether it makes sense looking for some alternative (again, the latest and shiniest is not what you need to aim for).


You don't need a driver for the Casio. It has the old-style round 5-pin MIDI terminals. They send and receive MIDI. That's it. No driver required.

You MAY have an issue with the MIDI interface you have bought to connect the 5-pin MIDI cables to your computer.

But I think it's likely that the Casio is in one of its Layered or Split modes where it sends on more than one MIDI channel.

Here's the manual.



In short, yes. This is actually a tricky question because it depends on what you're trying to do, how cheap, and how simply, you want to do it.

If I asked you to build a midi keyboard from scratch, could you do it? In fact, I've done essentially what you're asking about - I built a midi keyboard from the keybed existing in a cheap casio I bought at Goodwill. I'll spare you the technical details but I'll try to give you an idea of the scope of the project. The keyboard could only emit sound, no midi. I connected the keys to an Arduino development board and wrote code which interpreted the keys input and output midi via the Arduino's USB cord.

For more technical detail, here's a brief explanation: First I removed the keybed and cut the wires which connect to the button matrix. Then I connected those wires to a shift register, and from the shift register into my Arduino. Then I wrote code which decoded the shift register input, which now represented my button matrix. Then I wrote code to decode the button matrix which I reversed engineered, mostly with a multimeter. Finally, I used an Arduino midi library to output midi over the serial bus and used an intermediary program to read that midi over USB and act as a virtual midi device which could be recognized by Ableton. This took some time. If I had to do it again, I could but it would take me just as long since most of the challenge depends on decoding the button matrix which will depend on what keyboard you get. Please feel free to ask any questions. I did this a year ago but there wasn't enough documentation online and I had to figure a lot out on my own. If possible I hope I can make it easier for you if you do go about the project.

  • Thanks for the reply. Unfortunately, I don't really want to break into my keyboard, I'm just trying to make it work via conventional means. I can't even code, not to talk about wiring circuits and working with an arduino.
    – Press Play
    Aug 13, 2018 at 9:59
  • An interesting answer, but not an answer to this question! This keyboard already has MIDI implemented.
    – Laurence
    Aug 13, 2018 at 12:19
  • Ha! Ok, didn't realize I misunderstood the question but I'll leave the answer for now. Aug 13, 2018 at 13:48

Google says that buying a Viewcon device might not have been a good idea.

There are rumors that using a different driver might work better.

Anyway, to ensure that you get a USB MIDI interface that actually works, you should choose a well-known brand, such as E-Mu, Edirol, M-Audio, Miditech, MoTU, Roland, or Yamaha.


I too have an old Casio (CTK 651). I use an M-Audio midisport 2x2 midi/USB adapter that has worked solidly for years, although I am sure there are many others that would work just as well. If this is a long term hobby/interest for you, consider just getting a new midi controller. They are relatively inexpensive and the gain in functionality will be worth the investment in the long run.

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