Tubbutec OrganDonor Yamaha SK-10 Installation Guide
- October 30, 2023
- Tubbutec
Table of Contents
OrganDonor
Installation manual for Yamaha SK-10
OrganDonor Yamaha SK-10
Tools you will need:
- Soldering iron
- Wire stripper
- Metal drill 3.5mm (or similar)
- Metal drill for a 15mm hole (stepping drill for example)
- Center punch
- Screw driver
Included in the kit:
- OrganDonor Main Board with installed PNP transistor
- 3x organ Donor Switch Board, 3×20 pin connector
- Analog switch connection: 3×20 – 21cm, 29cm, 55cm
- Interconnect cables: 1x 80cm, 1x 23cm, 1x 12cm
- Midi connector assembly
- Power connector
- Learn button
- 2x screw 2,9×9,5, 3x screw M3x16mm
- Midi socket drill guide
- 2x M3 bolt, 2xM3 nut for midi socket
Principle of operation
OrganDonor uses analog switches to simulate keyboard presses directly. Normally this would require to solder two wires for each key. Luckily this can often be avoided by grouping common signals. OrganDonor features solder jumpers to connect common signals on the back of each analog switch board. We already connect these jumpers for you. In the case of the Yamaha SK-10 there are 8 common signals.
Main board installation
Mount the main board with the 2 2,9×9,5 screws directly on the bottom of the
synthesizer, right next to the power transformer.
Solder the power cable assembly to the
bottom side of the regulator board as shown. The red wire of the cable
assembly gets soldered to one of the black cables on the bottom side of the
connector, the black and yellow wires get soldered to the yellow wires on the
bottom side of the connector.
Switch board installation
Before you mount the switchboards you need to prepare a few things. First you need to disassemble the keyboard pcb by removing all screws. Then you need to cut a thread in the marked holes (M3 – if you don’t have an M3 thread cutter you can optionally order one with the kit). Next you need to cut away a bit of the rubber strip
directly under the keyboard connector. This is where the common connections
get routed to the connector.
Now reassemble the keyboard pcb, but use only the 3 M3x16mm to
screw the switch boards to the holes you cut the threads in. Leave the other
screws away for now.
Install the interconnection cables and the switch cable
assemblies. Cut the cables to length and strip the wires.
Now solder the wires to the Anode side of the diodes on the keyboard pcb.
ATTENTION: the first wire of switch board 1 gets soldered to the second diode on the keyboard pcb and so on. More on that later.
Switch board 1:
Wire 2 gets cut.
Wires 3-18 get soldered to diodes 2-17 on the keyboard pcb.
Switch board 2:
Wire 1 gets cut.
Wires 3-18 get soldered to diodes 18-33 on the keyboard pcb.
Wire 20 gets cut
Switch board 3:
Wires 3-18 get soldered to diodes 34-49 on the keyboard pcb.
Wire 19 gets cut.
Next you need to solder the common connection wires to the backside of the keyboard connector on the keyboard pcb. To do so disassemble the keyboard pcb again carefully to get access to the backside.
Switch board 1:
Wire 1 gets soldered to the first pin of the keyboard connector (counted from the left in the picture).
Wire 19 to the second pin.
Wire 20 to the third pin.
Switch board 2:
Wire 2 gets soldered to the fourth pin of the keyboard connector.
Wire 19 the fifth pin.
Switch board 3:
Wire 1 gets soldered to the sixth pin of the keyboard connector.
Wire 2 to the seventh pin.
Wire 20 to the eighth pin.
Next up is the switch contact for the lowest key. This key gets triggered via a PNP transistor on the main board. Solder the black cable coming from that transistor also to pin 1 of the keyboard connector. The red wire coming from the transistor gets soldered to the Anode side of the first diode on the keyboard pcb.
Now you
can reassemble the keyboard pcb and secure all the screws. Make sure to route
the common wires through the cut-out in the rubber strip.
Installing the midi socket
The midi socket can be installed on the back of the machine like we did. Use
the provided drill guide to center punch the locations of the 3 holes. The two
small holes need to be about 3.5mm in diameter, the large hole 15mm. Here we
typically use a stepping drill.
Installing the learn button
The optional learn button can be used to set midi channel. It needs to be
connected to the IO “2” and “G” pin on the main board. (The back of the main
board has labels on it). Wires are not included in the kit.
Press the learn button and while it is pressed send a midi note on any midi
channel. OrganDonor will use this midi channel from now on. These settings are
saved.
Configuration
We already flashed the corresponding configuration file to Organ Donor. There
is, however, a software configuration tool available, in case you want to play
around with settings and key assignments.
You`ll find the configurator here:
https://tubbutec.de/files/organDonor/tubbutecOrganDonorConfigurator.html
This is a browser application, it works with Chrome and Safari right away,
Firefox needs to be configured for web MIDI.
The configurator allows you to upload your settings directly from your browser
to OrganDonor, safe and load settings and export settings as SysEx files for
uploading to Organ Donor via another SysEx tool.