CHD Elektroservis K770-KBD User manual

K770
K770K770
K770-
--
-KBD
KBDKBD
KBD
MIDI Interface for
MIDI Interface forMIDI Interface for
MIDI Interface for
Korg 770 / 700S / 900PS Keyboard
Korg 770 / 700S / 900PS KeyboardKorg 770 / 700S / 900PS Keyboard
Korg 770 / 700S / 900PS Keyboard
Model 8
Model 8Model 8
Model 8-
--
-430
430430
430
Version 1.0
Version 1.0Version 1.0
Version 1.0
Installation Manual for Korg 900PS
Installation Manual for Korg 900PSInstallation Manual for Korg 900PS
Installation Manual for Korg 900PS
© 2019 CHD Elektroservis
© 2019 CHD Elektroservis© 2019 CHD Elektroservis
© 2019 CHD Elektroservis

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
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Contents:
Contents:Contents:
Contents:
1
11
1
GENERAL INFORMATION
GENERAL INFORMATIONGENERAL INFORMATION
GENERAL INFORMATION ................................
................................................................
................................................................
................................................................
................................................................
................................................................
................................................................
................................................................
................................ 3
33
3
1.1 MIDI INTERFACE KIT PARTS............................................................................................................................. 3
2
22
2 MIDI INTERFACE INSTALLATION
MIDI INTERFACE INSTALLATIONMIDI INTERFACE INSTALLATION
MIDI INTERFACE INSTALLATION ................................
................................................................
................................................................
................................................................
................................................................
................................................................
.......................................................
..............................................
....................... 4
44
4
2.1 OPEN THE INSTRUMENT................................................................................................................................. 4
2.2 DRILLING OF HOLES FOR MIDI SOCKETS............................................................................................................ 6
2.3 MIDI SOCKETS MOUNTING ............................................................................................................................. 7
2.4 DRILLING OF HOLES FOR BUTTON AND INDICATION LED..................................................................................... 7
2.5 BUTTON AND INDICATION LED MOUNTING...................................................................................................... 8
2.6 POWER SUPPLY CABLE MOUNTING.................................................................................................................. 8
2.7 KEYBOARD CONTROL SIGNALS CABLE MOUNTING ............................................................................................. 9
2.8 THE INTERFACE BOARD MOUNTING .............................................................................................................. 10
2.9 INTERFACE ADJUSTMENT ............................................................................................................................. 12
2.10 FINISHING OF THE INSTALLATION.................................................................................................................. 13
3
33
3 INSTALLATION TIPS
INSTALLATION TIPSINSTALLATION TIPS
INSTALLATION TIPS ................................
................................................................
................................................................
................................................................
................................................................
................................................................
................................................................
................................................................
......................................
............
...... 15
1515
15
3.1 MIDI – THRU/OUT OUTPUT .......................................................................................................................... 15
3.2 RESET BUTTON AND INDICATION LED ............................................................................................................ 15

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
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No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
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1
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1
GENERAL INFORMATION GENERAL INFORMATIONGENERAL INFORMATION
GENERAL INFORMATION
Figure 1.1
Figure 1.1 Figure 1.1
Figure 1.1 –
––
– Connection to instrument circuits
Connection to instrument circuits Connection to instrument circuits
Connection to instrument circuits
K770-KBD MIDI interface controls VCO and GATE
generator of the Korg 900PS synthesizer. Simplified
block schematics of the interface installation in the
instrument shows fig. 1.1.
The interface board looks very similarly for Korg 770,
700S, 900PS and M500 but there are a differences in
some components. It is recommended to check if you
have the correct model. The instrument model
identification label on the interface board (see fig. 1.2)
specifies the Korg instrument type: K770 is interface
for Korg 770, 700S and 900PS, KM500 is interface for
Korg M500 Micropreset.
Figure 1.2
Figure 1.2 Figure 1.2
Figure 1.2 –
––
– Identification labels
Identification labels Identification labels
Identification labels
The interface firmware can be revised. Actual version of the
firmware is printed on the identification label on the interface’s
processor (see fig. 1.2). It is also possible to read the actual
version of firmware from the interface by MIDI System Exclusive
message.
1.1
1.11.1
1.1
MIDI INTERFACE KIT PARTS MIDI INTERFACE KIT PARTSMIDI INTERFACE KIT PARTS
MIDI INTERFACE KIT PARTS
MIDI interface kit contents all necessary parts for installation
incl. all support and coupling elements. The delivery also
includes both installation and operation manuals in printed
form. Please check if the delivery is complete before the
installation (see fig. 1.1.1).
Figure 1.1.1
Figure 1.1.1 Figure 1.1.1
Figure 1.1.1 –
––
– Parts of the interface kit
Parts of the interface kit Parts of the interface kit
Parts of the interface kit
The K770-KBD interface kit
delivery contents:
(1) MIDI Interface board
(2) 2x DIN-5 socket with cable
(3) Bunched cables for power
supply
(4) Bunched cables with
button and LED
(5) Bunched cables of
keyboard control signals
(6) Coupling elements (LED
holder, screws, nuts,
washers, insulation tube
and tightening strips)
(7) Owner’s and Installation
manuals in printed form

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
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2
MIDI INTERFACE INSTALLATION MIDI INTERFACE INSTALLATIONMIDI INTERFACE INSTALLATION
MIDI INTERFACE INSTALLATION
Mounting the interface in the Korg 900PS synthesizer is very easy. If you follow the instructions from this
manual, there should be no major problems during the installation. The interface installation procedure is
thoroughly described in the following chapters. Please follow these instructions accurately to avoid any damage
of the instrument.
Attention! Disconnect the instrument form the mains prio
Attention! Disconnect the instrument form the mains prioAttention! Disconnect the instrument form the mains prio
Attention! Disconnect the instrument form the mains prior to the installation. There is a risk of the
r to the installation. There is a risk of the r to the installation. There is a risk of the
r to the installation. There is a risk of the
electric shock!
electric shock!electric shock!
electric shock!
Attention! Observe precautions for handling electrostatic discharge sensitive devices!
Attention! Observe precautions for handling electrostatic discharge sensitive devices!Attention! Observe precautions for handling electrostatic discharge sensitive devices!
Attention! Observe precautions for handling electrostatic discharge sensitive devices!
The producer is not responsible for any eventual mechanical or electrical damage of the Korg
The producer is not responsible for any eventual mechanical or electrical damage of the Korg The producer is not responsible for any eventual mechanical or electrical damage of the Korg
The producer is not responsible for any eventual mechanical or electrical damage of the Korg
instrument
instrumentinstrument
instrument caused by the infringement of the described installation procedure or by careless
caused by the infringement of the described installation procedure or by careless caused by the infringement of the described installation procedure or by careless
caused by the infringement of the described installation procedure or by careless
manipulation during the installation of the MIDI interface!
manipulation during the installation of the MIDI interface!manipulation during the installation of the MIDI interface!
manipulation during the installation of the MIDI interface!
It is recommended to calibrate the instrument accordingly to the instructions in service manual of the
It is recommended to calibrate the instrument accordingly to the instructions in service manual of the It is recommended to calibrate the instrument accordingly to the instructions in service manual of the
It is recommended to calibrate the instrument accordingly to the instructions in service manual of the
instrume
instrumeinstrume
instrument prior the interface installation. This ensures trouble
nt prior the interface installation. This ensures troublent prior the interface installation. This ensures trouble
nt prior the interface installation. This ensures trouble-
--
-free operation of the interface.
free operation of the interface.free operation of the interface.
free operation of the interface.
2.1
2.12.1
2.1
OPEN THE INSTRUMENT OPEN THE INSTRUMENTOPEN THE INSTRUMENT
OPEN THE INSTRUMENT
Please keep all original screws and washers removed during the instrument opening procedure described in
paragraphs below. They will be used again after the MIDI kit installation is finished.
a) Unscrew four self-tapping screws on the bottom side of the instrument (fig. 2.1.1). Then remove the front
panel - cover under the instrument’s keyboard (fig. 2.1.2).
b) Unscrew the nut holding the cable of touch sensor on the front panel and remove the cable so that it is not
damaged during the next steps (fig. 2.1.2).
Figure 2.1.1
Figure 2.1.1Figure 2.1.1
Figure 2.1.1
Figure 2.1.2 Figure 2.1.2Figure 2.1.2
Figure 2.1.2
Figure 2.1.3
Figure 2.1.3Figure 2.1.3
Figure 2.1.3
Figure 2.1.4 Figure 2.1.4Figure 2.1.4
Figure 2.1.4

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
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No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
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c) Unscrew eight screws (two metric and six self-tapping) from top part of the instrument cover (fig. 2.1.3).
Then remove the top cover.
d) Unscrew six screws from both wood side plates (two from outer side and one from inner side on each of the
side plates - fig. 2.1.4). Then remove the wood sides.
e) Unscrew three screws on the bottom side of the instrument (fig. 2.1.5) and three screws inside the
instrument (fig. 2.1.6).
f) Unscrew four screws outside the instrument from the left and right side (fig. 2.1.7).
g) Now, the block of instrument’s control panel can be removed from the instrument - lift it up and then flip it
to back. All instrument’s parts and boards needed for the interface installation are now accessible (fig. 2.1.8).
Figure 2.1.5
Figure 2.1.5Figure 2.1.5
Figure 2.1.5
Figure 2.1.6 Figure 2.1.6Figure 2.1.6
Figure 2.1.6
Figure 2.1.7
Figure 2.1.7Figure 2.1.7
Figure 2.1.7
Figure 2.1.8
Figure 2.1.8Figure 2.1.8
Figure 2.1.8

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
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2.2
2.22.2
2.2
DRILLIN DRILLINDRILLIN
DRILLING OF HOLES FOR MIDI SOCKETS
G OF HOLES FOR MIDI SOCKETSG OF HOLES FOR MIDI SOCKETS
G OF HOLES FOR MIDI SOCKETS
Figure 2.2.1
Figure 2.2.1Figure 2.2.1
Figure 2.2.1
The interface has both MIDI input and output. Only
MIDI input is necessary for the basic interface
operation. MIDI output has not to be installed – see
chapter 3.1. Nevertheless, having both MIDI input and
output (MIDI-IN and MIDI-THRU/OUT sockets) is more
convenient for an easy integration in the more
advanced MIDI system.
a) The suitable place for the MIDI sockets montage is
on the left side of rear panel of the instrument near to
fuse holder (fig. 2.2.1). You have to drill six holes to the
panel.
b) Drill two holes with diameter 16 mm and four holes with diameter 3,2 mm to the rear panel of the
instrument as shown on fig. 2.2.2 (all dimensions are in mm). Use sharp drills and work care
work carework care
work carefully
fullyfully
fully so that the
cover is not scratched and other parts of the instrument are not damaged!
Figure 2.2.2
Figure 2.2.2Figure 2.2.2
Figure 2.2.2
c) Clean the edge of the holes with small rasp or tip of bigger drill from both sides of the panel after the holes
are drilled.
c) Clean all iron
Clean all iron Clean all iron
Clean all iron sawdust and raspings from the inside of the instruments
sawdust and raspings from the inside of the instrumentssawdust and raspings from the inside of the instruments
sawdust and raspings from the inside of the instruments, they can cause short circuits or serious
electrical damage if left inside the instrument. Please clean the instrument carefully!

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
7
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2.3
2.32.3
2.3
MIDI SOCKETS MOUNTING MIDI SOCKETS MOUNTINGMIDI SOCKETS MOUNTING
MIDI SOCKETS MOUNTING
a) Pull flat connectors of MIDI cables (from the interface accessory) through 16 mm holes in the instrument’s
rear panel from outer side and insert DIN sockets into the holes. Both MIDI cables are identical and can be
swapped.
Figure 2.3.1
Figure 2.3.1 Figure 2.3.1
Figure 2.3.1
Figure 2.3.2 Figure 2.3.2 Figure 2.3.2
Figure 2.3.2
b) Fix DIN sockets to the drilled holes using screws, nuts and tooth lock washers from the interface accessory
(fig. 2.3.1).
c) It is recommended to label the DIN sockets ("MIDI IN", "MIDI THRU/OUT" for example) with self-adhesive foil
glued near the sockets (fig. 2.3.2).
2.4
2.42.4
2.4
DRILLING O DRILLING ODRILLING O
DRILLING OF HOLES FOR BUTTON AND INDICATION LED
F HOLES FOR BUTTON AND INDICATION LEDF HOLES FOR BUTTON AND INDICATION LED
F HOLES FOR BUTTON AND INDICATION LED
There are two control elements on the interface - button and bi-color LED. They are not necessary for the
interface operation, so they need not to be installed (if you prefer to maintain the vintage status of the
instrument) – see chapter 3.2. Nevertheless having both of them installed is more convenient for easier device
control.
a) If you decide to install the LED and the button, the suitable place for them is on the right side of the front
panel - the cover under the instrument’s keyboard (fig. 2.4.1). In that case, you have to drill two holes in the
panel as shown on fig. 2.4.2 (all dimensions are in mm).
Figure 2.4.1
Figure 2.4.1Figure 2.4.1
Figure 2.4.1
Figure 2.4.2 Figure 2.4.2 Figure 2.4.2
Figure 2.4.2
a) Drill one hole with diameter 7 mm (for RESET button) and one hole with diameter 6,5 mm (for indication LED)
to the panel – see pic. 2.4.2. Use sharp drills and work carefully
work carefullywork carefully
work carefully so that the cover is not scratched during the
drilling!
b) Clean the edge of all holes with small rasp or with point of bigger drill after the holes are drilled.

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
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No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
8
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2.5
2.52.5
2.5
BUTTON AND INDICATION LED MOUNTING BUTTON AND INDICATION LED MOUNTINGBUTTON AND INDICATION LED MOUNTING
BUTTON AND INDICATION LED MOUNTING
a) Insert LED holder (from the interface accessory) into 6,5 mm hole in the instrument’s front panel from the
outer side. Pull the lock ring of the LED holder over the supplied LED. Then insert the LED into the holder (from
inner side of the instrument’s panel) and fix it by the overthrust of the ring on the holder (fig. 2.5.1).
b) Insert button into 7 mm hole in the instrument’s panel from inner side. Fix the button to the panel with the
spring washer and nut (fig. 2.5.2).
Figure 2.5.1
Figure 2.5.1 Figure 2.5.1
Figure 2.5.1
Figure 2.5.2 Figure 2.5.2 Figure 2.5.2
Figure 2.5.2
2.6
2.62.6
2.6
POWER SUPPLY CABLE MOUNTING POWER SUPPLY CABLE MOUNTINGPOWER SUPPLY CABLE MOUNTING
POWER SUPPLY CABLE MOUNTING
The power supply cable from the interface accessory is fitted with 3-pin flat connector (fig. 2.6.1). It is advisable
to shorten wires of this cable bunch to the required lengths as shown on fig. 2.6.1
1
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1
. Wires of the cable bunch
must be connected to several pads at the instrument’s power supply board (fig. 2.6.2).
Figure 2.6.1
Figure 2.6.1Figure 2.6.1
Figure 2.6.1
Figure 2.6.2
Figure 2.6.2Figure 2.6.2
Figure 2.6.2
a) Solder the red wire Nr. 3 “+20V“ to
“+Vcc” pad on the instrument’s power
supply board (fig. 2.6.2). Two orange
wires of original bunched cables are
already soldered here.
b) Solder the black wire Nr. 2 “GND“ to
“GND” pad on the instrument’s power
supply board (fig. 2.6.2). Two black
wires of original bunched cables are
already soldered here.
c) Solder the blue wire Nr. 1 “-10V“ to
“-Vee” pad on the instrument’s power
supply board (fig. 2.6.2). Two green
wires of the original bunched cables
are already soldered here.
1
The delivered power supply cable is universal for all 770, 700S and 900PS instruments so its original length does not meet the 900PS exactly.

Korg 900PS MIDI Interface
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Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
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2.7
2.72.7
2.7
KEYBOARD CONTRO KEYBOARD CONTROKEYBOARD CONTRO
KEYBOARD CONTROL SIGNALS CABLE MOUNTING
L SIGNALS CABLE MOUNTINGL SIGNALS CABLE MOUNTING
L SIGNALS CABLE MOUNTING
The keyboard control signals cable from the interface accessory is fitted with 4-pin flat connector (fig. 2.7.1). It
is advisable to shorten all wires of this cable bunch to the required length (cca 300 mm) as shown on fig. 2.7.1
2
22
2
.
Wires of the cable bunch must be connected to the instrument’s keyboard and between the instrument’s
keyboard and VCO (KLM22) board (fig. 2.7.2 and fig. 1.1).
Figure 2.7.1
Figure 2.7.1Figure 2.7.1
Figure 2.7.1
Figure. 2.7.2
Figure. 2.7.2Figure. 2.7.2
Figure. 2.7.2
a) Unsolder the white wire (leads from the KLM22 board) from soldering lug on the instrument’s keyboard (fig.
2.7.3).
b) Place heat-shrink insulation tube
φ 2 mm (from the interface accessory) on yellow wire Nr. 2 “OUT” of the
keyboard control signals cable and solder the yellow wire to white wire freed from the soldering lug (fig. 2.7.4).
Figure 2.7.3
Figure 2.7.3Figure 2.7.3
Figure 2.7.3
Figure 2.7.4 Figure 2.7.4Figure 2.7.4
Figure 2.7.4
c) Isolate the connection with the insulation tube and heat it (with a hot-flue pistol for example) until it shrinks
tightly to the cables.
2
The delivered keyboard cable is universal for all 770, 700S and 900PS instruments so its original length does not meet the 900PS exactly.

Korg 900PS MIDI Interface
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Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
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10
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d) Solder green wire Nr. 1 “IN” of the interface cable to the soldering lug on the instrument’s keyboard (fig.
2.7.5).
e) Solder red wire Nr. 3 “REF“ of the interface cable to lug on the instrument’s keyboard where a brown wire is
already soldered (fig. 2.7.6). Work carefully – the soldering lug is less accessible (under a resistor).
f) Solder black wire Nr. 4 “GND“ of the interface cable to thick wire (common bus) of the instrument’s keyboard
– to pad where a black wire is already soldered (fig. 2.7.6).
Figure 2.7.5
Figure 2.7.5Figure 2.7.5
Figure 2.7.5
Figure 2.7.6 Figure 2.7.6Figure 2.7.6
Figure 2.7.6
2.8
2.82.8
2.8
THE INTE THE INTETHE INTE
THE INTERFACE BOARD MOUNTING
RFACE BOARD MOUNTINGRFACE BOARD MOUNTING
RFACE BOARD MOUNTING
Figure. 2.8.1
Figure. 2.8.1Figure. 2.8.1
Figure. 2.8.1
a) The interface board will be placed
on the bottom metal cover of the
instrument – to the right of the power
supply board (fig. 2.8.1).
b) Cleanse the part of rear panel inside
of the instrument for the interface
board placement (fig. 2.8.1). Use a
chemical cleaner to remove all dirt and
grease.
c) Remove the protective foil form the
self-adhesive supports of the interface
board (fig. 2.8.2).
Figure 2.8.2
Figure 2.8.2Figure 2.8.2
Figure 2.8.2
Figure 2.8.3 Figure 2.8.3 Figure 2.8.3
Figure 2.8.3
d) Attach the interface board to the instrument’s cover so that the board side with two connectors X4 (“KBD”)
and X5 (“PWR”) points to the left, towards the power supply board as shown on the figure 2.8.3. Than fix the
self-adhesive supports by pressing down to the cover.

Korg 900PS MIDI Interface
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Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
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11
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e) Plug the 3-pin connector of the bunched cables lead from the power supply board to X5 (“PWR”) plug head
on the interface board. Orientation of the connector is given by the connector lock so it cannot be plugged
reversely (fig. 2.8.4).
f) Plug 4-pin connector of the bunched cables lead from keyboard to X4 (“KBD”) plug head on the interface
board. Orientation of the connector is given by the connector lock again (fig. 2.8.4).
g) Plug two 3-pin connectors of the MIDI cables to X1 (“I”) and X2 (“O”) plug heads on the interface board.
Orientation of the connectors is given by the connector lock again but be sure that the connectors are not
exchanged: MIDI input must be plugged to X1 head and MIDI output to X2 head (fig. 2.8.4).
h) Pull the 4-pin connector of the bunched cables (leads from button and LED mounted on front panel) under
the instrument’ keyboard to inside of the instrument (fig. 2.8.5).
i) Fix the brown cable back to the touch sensor on instrument’s front panel with the original nut (fig. 2.8.5).
j) Plug the 4-pin button and LED cable connector to X3 (“CTRL”) plug head on the interface board. Orientation of
the connector is given by the connector lock again (fig. 2.8.4).
Figure 2.8.4
Figure 2.8.4Figure 2.8.4
Figure 2.8.4
Figure 2.8.5
Figure 2.8.5Figure 2.8.5
Figure 2.8.5
Figure 2.8.6 Figure 2.8.6 Figure 2.8.6
Figure 2.8.6
k) Align new keyboard control cable (“KBD”) and power supply cable (“PWR”) and fix them together to the
original cables with plastic stripes from the interface accessory. Fix also the MIDI cables and control cable (fig.
2.8.6)
l) Place the block of instrument’s control panel back to its original position (fig. 2.8.7).

Korg 900PS MIDI Interface
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Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
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430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
12
1212
12
Figure 2.8.7
Figure 2.8.7Figure 2.8.7
Figure 2.8.7
2.9
2.92.9
2.9
INTERFACE ADJUSTMENT INTERFACE ADJUSTMENTINTERFACE ADJUSTMENT
INTERFACE ADJUSTMENT
Figure 2.9.1
Figure 2.9.1Figure 2.9.1
Figure 2.9.1
There are two variable resistors on the interface board
labeled “OFFSET” and “RANGE” (fig. 2.9.1). They must be
adjusted before the interface is used. Adjustment
procedure is following
3
33
3
:
a) Connect MIDI output of your MIDI master keyboard (or
PC / sequencer / DAW) to MIDI input of the interface
4
44
4
.
b) Connect audio output of the instrument to a tuner or
to a frequency meter.
c) Set all controllers on the instrument’s panels to a clear
sound without any modulation:
• PITCH knob Æ to middle position
• HARMONICS switches Æ I. and II. off (upper position) / III. on (lower position)
• ATTACK/SUSTAIN switch Æ to CONTROL CONTROLCONTROL
CONTROL (lower position)
• VOLUME slider Æ to 10
1010
10 (MAX.)
• HARMONICS sliders Æ 16’, 8’ and 2’ to 0
00
0 / 4’ to 10
1010
10
• ATTACK and SUSTAIN sliders Æ both to 0
00
0
• REPEAT, FORTE, PITCH BEND, VIBRATO and PORTAMENTO switches Æ all off (middle position)
• TRAVELER slider Æ to 10 1010
10 (fully to right)
• OCTAVE switch Æ to M
MM
M (middle position)
Positions of other controllers on instrument’s panel are not significant.
d) Plug instrument's power supply cable to a mains socket and switch the instrument on by main switch joined
with the VOLUME knob. Attention
Attention Attention
Attention -
--
- work very carefully during whole adjustment procedure
work very carefully during whole adjustment procedure work very carefully during whole adjustment procedure
work very carefully during whole adjustment procedure -
--
-
there is a risk of there is a risk of there is a risk of
there is a risk of
electric shock!
electric shock!electric shock!
electric shock!
e) Now, the interface is in "Stand-by" mode - the interface’s indication LED is off. If not, press the "RESET"
button of the interface.
f) Wait a few minutes
Wait a few minutesWait a few minutes
Wait a few minutes to stabilize the temperature of all instrument circuits.
g) Measure the voltage between pins of the "TP" jumper head (fig. 2.9.1) with a quality digital multimeter. It
should be zero volts exactly. If it is not, adjust it with "OFFSET” variable resistor on the interface board (fig.
2.9.1).
3
It is suppossed that the interface is in "Factory Reset" status before the adjustment procedure. If it is not, send the F0 00 20 21 7F 54 50 03 7F 5A
F0 00 20 21 7F 54 50 03 7F 5A F0 00 20 21 7F 54 50 03 7F 5A
F0 00 20 21 7F 54 50 03 7F 5A
F7 [hex]
F7 [hex]F7 [hex]
F7 [hex] SysEx message to the intarface first.
4
Set transmit MIDI Channel to number 1 on the master keyboard.

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
13
1313
13
Figure 2.9.2
Figure 2.9.2Figure 2.9.2
Figure 2.9.2
h) Press the C3 key on the instrument’s keyboard (fig. 2.9.2) - indication bi-
color LED remains off.
i) Measure the output tone frequency by the tuner (frequency meter). It
should be 1047 Hz approx. Remember the measured tone frequency. Then
release the C3 key.
j) Press the C3 key on the master keyboard (i.e. send MIDI Note Nr. 84 to the interface) and hold it. The
indication LED will light in green.
k) Check the output tone frequency by the tuner (frequency meter) again. It must be the same as the frequency
measured in paragraph i). If it is not, adjust it with "RANGE” variable resistor on the interface board (fig. 2.9.1).
l) Release the C3 key on the master keyboard. Switch the instrument off and disconnect the power supply cable
disconnect the power supply cable disconnect the power supply cable
disconnect the power supply cable
from mains socket
from mains socketfrom mains socket
from mains socket.
2.10
2.102.10
2.10
FINISHING OF THE INS FINISHING OF THE INSFINISHING OF THE INS
FINISHING OF THE INSTALLATION
TALLATIONTALLATION
TALLATION
Now assembly all instrument parts of the instrument together. It is a reverse procedure than described in
chapter 2.1. Use the original screws and do not forget to place the washers to their original places.
a) Fix the block of instrument’s control panel with four screws (M4) outside the instrument and three screws
(M3) inside the instrument (fig. 2.10.1).
b) Fix the block of instrument’s control panel with three metric screws (M3) and front panel with four self-
tapping screws – all from the bottom side of the instrument (fig. 2.10.2).
Figure 2.10.1
Figure 2.10.1 Figure 2.10.1
Figure 2.10.1
Figure 2.10.2 Figure 2.10.2 Figure 2.10.2
Figure 2.10.2
c) Fix both wood side plates to the instrument with six screws (two from outer side and one from inner side on
each of the sides – fig. 2.10.3).
d) Fix the top cover to the instrument with eight screws (two metric and six self-tapping – fig. 2.10.4).
Figure 2.10.3
Figure 2.10.3 Figure 2.10.3
Figure 2.10.3
Figure 2.10.4 Figure 2.10.4 Figure 2.10.4
Figure 2.10.4

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
1
4
141
4
14
The installation of the MIDI interface kit is now finished and the Korg 900PS instrument is prepared for MIDI
communication.
Please read carefully user manual of the interface before usage of modified instrument.
Please read carefully user manual of the interface before usage of modified instrument.Please read carefully user manual of the interface before usage of modified instrument.
Please read carefully user manual of the interface before usage of modified instrument.
Figure 2.10.5
Figure 2.10.5Figure 2.10.5
Figure 2.10.5

Korg 900PS MIDI Interface
Korg 900PS MIDI InterfaceKorg 900PS MIDI Interface
Korg 900PS MIDI Interface
K770
K770 K770
K770-
--
-KBD
KBDKBD
KBD
Installation Manual Installation ManualInstallation Manual
Installation Manual
8
88
8-
--
-430 / v. 1.00
430 / v. 1.00430 / v. 1.00
430 / v. 1.00
Copyright © 2019 CHD Elektroservis. All rights reserved.
No part of this publication may be reproduced in any form without the written permission of CHD Elektroservis.
15
1515
15
3
33
3
INSTALLATION TIPS INSTALLATION TIPSINSTALLATION TIPS
INSTALLATION TIPS
3.1
3.13.1
3.1
MIDI MIDI MIDI
MIDI –
––
– THRU/OUT OUTPUT
THRU/OUT OUTPUT THRU/OUT OUTPUT
THRU/OUT OUTPUT
Figure 3.1
Figure 3.1Figure 3.1
Figure 3.1
K770-KBD interface has both MIDI input and output.
However, only MIDI input is necessary for basic
operation of the interface (i.e controlling the
instrument by MIDI commands). MIDI THRU/OUT
output connector need not to be installed at all. If you
don’t require transfer of MIDI data to another MIDI
devices (THRU function ) or reverse communication of
the interface with host system (OUT function). In such
case, X2 connector (labeled “O
OO
O”) on the interface board
will remain unused (see pic. 3.1).
3.2
3.23.2
3.2
RESET BUTTON AND INDIC RESET BUTTON AND INDICRESET BUTTON AND INDIC
RESET BUTTON AND INDICATION LED
ATION LEDATION LED
ATION LED
Installation of the reset button and indication LED isn’t necessary as well. You don´t need to install this bunched
cables if you don’t want to damage the instrument’s panel by drilling. In such case, X3 connector (labeled
“CTRL
CTRLCTRL
CTRL”) will remain unused (see fig. 3.1).
It is also possible to install only the indication LED on instrument’s panel. In such case, disconnect the button
from bunched cables (cut-off yellow and black wires as shown on fig. 3.2).
If the button is not installed, the interface operation is unaffected. The only limitation is that the reset of the
interface can be done only by turning the instrument off and on or by MIDI commands sent to the interface
(see user manual of the interface).
Figure 3.2
Figure 3.2Figure 3.2
Figure 3.2
This manual in PDF form
This manual in PDF formThis manual in PDF form
This manual in PDF form is available at manufacturer’s web pages.
is available at manufacturer’s web pages. is available at manufacturer’s web pages.
is available at manufacturer’s web pages.
KORG 770 / 700S / 900PS MIDI Interface
Model K770-KBD, Nr. 8-430, ver. 1.00
Document: 843010-2_instal
Manufacturer: CHD Elektroservis, Czech Republic
www.chd-el.cz [e-mail]