Midifying Yamaha keyboards

Design Concepts
1

I wish to midify two Yamaha 44-key boards from an Electone B405. The keyboards have individual notes commoned across successive octaves together with octave identification leads working into a YM102100 chip. Is any software available to handle such multiplexed inputs?

If the answer is no, can the existing commoned wiring (isolated via individual diodes) be left operative to existing Yamaha circuitry while connecting individual keys to DIN inputs to enable both the Yamaha and MidiBox systems to run in parallel.

2

Hello Rufus,

how about…

http://ucapps.de/midio128.html

http://www.midibox.org/dokuwiki/doku.php?id=mbhp4066

http://www.subfrequenz.net/midibox/vss200/mbhp4066v1/MBHP4066V1.pdf

But I don’t know the YM102100 chip yet…

3

This guy did an awesome job on my old Yamaha PSS-140 (I think)

I bought it on ebay and had it shipped to him directly, he installed the MIDI-In upgrade and forwarded it to me!

It was an awesome keyboard, I traded it a few years ago :frowning:

http://highlyliquid.com/

4

Rufus,

do you happen to have some documentation for the B405 or a description of how the inputs are multiplexed? I will face a similar problem soon (MIDIfying a B75 organ keyboard), and I could not find a service manual yet…

5

Rufus,

do you happen to have some documentation for the B405 or a description of how the inputs are multiplexed? I will face a similar problem soon (MIDIfying a B75 organ keyboard), and I could not find a service manual yet…

Yes, I do have the B405 manual. The diagrams spread across several pages so I will try to work out a way of digitizing what you need for transmission. Patience is a virtue …

Rufus

6

Yes, I do have the B405 manual. The diagrams spread across several pages so I will try to work out a way of digitizing what you need for transmission. Patience is a virtue …

Rufus

post-9399-061214900 1298953731_thumb.jpg
post-9399-061214900 1298953731_thumb.jpg1232×1507 173 KB

7

I have finally been able to resolve my scanner problem and have now attached a copy of the Yamaha B405

keyboard wiring diagram. I hope this assists your project.

In my case, while the above suggestions from lemonhorse were welcome, they don’t quite provide the

answer I was looking for.

Regards,

Rufus

8

Hi Rufus,

don’t know what you want to do with the keyboard. Maybe your thread belongs more to midification than to design concepts. This eventually might help you: http://www.midibox.org/dokuwiki/doku.php?id=midiboxkb_-_using_a_c64_keyboard_as_input

'coz what you have there is a 4 by 12 scan matrix with switches and diodes, you only have to change the number of columns and rows in code and perhaps alter the note numbers. Than your little toy will work.

You will only need to solder a nice 30Pin conector to your dins and douts and connect it directly with your keyboard-scan-board.

Best regards,

clem!

9

Thanks Rufus,

apparently I missed your reply, when I get access to a proper computer again I’ll look at the schematics and see if it works the same way in my B75.

Best, ilmenator

10

Hello Rufus,

how about…

http://ucapps.de/midio128.html

http://www.midibox.org/dokuwiki/doku.php?id=mbhp4066

http://www.subfrequenz.net/midibox/vss200/mbhp4066v1/MBHP4066V1.pdf

But I don’t know the YM102100 chip yet…

Hi lemonhorse,

Thanks for your suggestions. midio128 is my fallback if no alternative offers. Both this

and mbhp4066 would require hacking the physical Yamaha keyboard pcd which I am loathe to do.

So I will keep looking a little longer for a software option before ruining that beautiful pcb.

Rufus

11

So I will keep looking a little longer for a software option before ruining that beautiful pcb.

I think you don’t have to ruin your PCB, it probably looks something like the attached schematic? At least this is valid for my B-75. I have not tried yet, but it looks like you could just hook up to the connectors on the PCBs and into the DIN modules.

Best, ilmenator

Edit: Well, if the Scan Matrix was 4x12, and not 8x8… shame!

[Yamaha Electone C-55n Keyboard Matrix.pdf](< base_url >/applications/core/interface/file/attachment.php?id=8717)