Korg KPR-77 User manual

Installation Instructions
Pre-assembled MIDI interface board
14-way ribbon cable with IDC plug
Push button switch
1x
1x
1x
Korg KPR-77 MIDI Interface
e kit includes the following:
Fine-tipped soldering iron & solder (tin / lead alloy recommended)
Phillips head screwdriver
Wire strippers
Small-gauge stranded core wire
You will need:
www.harryaxten.altervista.org

Installation
Remove any batteries if they are installed, and remove the 7x screws on the bottom of the
KPR-77. Carefully separate the two halves of the case by disconnecting the 2x at ex cables
and 3x Molex connectors.
Note: the two halves will still be joined by the wires going to the volume knob / power switch.
1.
Unscrew and remove the square board labelled ‘KLM-448A’ , found in the bottom half of the
case. Disconnect the at ex cable that joins it to the large voice board.
2.
Separate and fan out the wires of the included ribbon cable. It is recommended that you cut
the wires progressively shorter towards the striped end (Pin 1), as it will be connected at right
angles to the KLM-448A board. Strip a small amount of insulation on each, and tin the wire
with solder.
Solder the 14 wires to the underside of CN07 on the KLM-448A board as shown:
3.
KLM-448 A
114CN07
Pin 1
Unscrew and remove the voice and connector boards which occupy the bottom case (they are
attached together). Solder 2x 40cm lengths of wire to pins 4 & 5 of the SYNC connector as
shown. Either use dierent coloured wires, or mark the wires to tell them apart.
4.
Pin 5 Pin 4
SYNC
IN / OUTTOM-H

Replace the voice and connector boards, running the wires from the SYNC socket underneath
the voice board to the battery compartment. Be careful not to pinch any wires when replacing
the screws. Also replace the KLM-448A board, and reconnect its at ex cable.
5.
Carefully drill a hole for the MIDI Learn button in the top le corner of the back panel, above
the MIX / R output jack. Make sure the drill bit doesn’t hit anything when it emerges. Solder
2x 60cm lengths of wire to the terminals of the button and t it. Run the wires to the battery
compartment - you can bundle them with the wires from the power switch.
Note: if you don’t want to drill a hole in the case for the button, you could instead hot glue it to
inside of the battery door (in which case the wires need only be a few cm long).
6.
Solder a 40cm length of wire to the backlight switch (+5V), located on the sequencer board in
the top case as shown, and run it to the battery compartment.
7.
Button
Backlight switch
+5V

Solder the 5x newly installed wires to the pads on the MIDI board as shown:8.
Position the MIDI board in the battery compartment so that the ribbon cable from the KLM-
448A board, when folded, will reach the IDC socket. Plug the cable into the socket.
9.
Button
+5V
SYNC, pin 5
SYNC, pin 4
{
Reconnect the 2x at ex cables and 3x Molex connectors from the top case to the bottom
case. Close the KPR-77, ensuring that no wires are getting pinched or stretched. Replace the
7x case screws.
10.
MIDI Setup
e rst time you power on the KPR-77 aer installing the kit, it will not respond to notes as
the MIDI channel has not yet been initialised. To do so (and to change it at any point in the
future), press and hold the MIDI Learn button. While holding the button down, trigger a note
on the channel you want the KPR-77 to receive on.
e metronome bell will sound 3 times, indicating that the channel has been set. You can
now release the button. e channel will be stored in EEPROM and recalled on start-up. e
velocity of the note is taken as the accent threshold velocity.
MIDI Implementation
e KPR-77 will respond to MIDI Note On messages on a specic channel (see above). Drum
voices will play accented if the velocity is greater than the accent threshold velocity, depending
on the position of the ACCENT slider. Using MIDI will not aect the operation of the internal
sequencer - both can trigger voices simultaneously. e KPR-77’s original SYNC functionality
is unchanged, although it is not possible to use it at the same time as MIDI.
e drum voices are assigned to the following MIDI notes:
Bass Drum 36 (C3)
Snare Drum 38 (D3)
Closed Hi-Hat 42 (F#3)
Open Hi-Hat 46 (A#3)
High Tom 48 (C4)
Low Tom 45 (A3)
Hand Claps 39 (D#3)
Cymbal 49 (C#4)
Metronome (Click) 37 (C#3)
Metronome (Bell) 56 (G#4)