KORG DW 8000 SERVICE MANUAL

Page 2

1. SPECIFICATIONS

Keyboard

Voice

OSCI

0802

Auto bend

Noise

VCF

VCF EG

VCA EG

MG

Bend

Portamento

Digital delay

After touch

Key assign
mode

MIDI

61 keys (C ~ C), Initial Touch/After
Touch

8 voice

Octave (16', 8, 4'), Waveform (1 ~
16), Level adjustment

Octave (16', 8', 4), Waveform (1 ~
16), Interval (Unison, Minor 3rd,
Major 3rd, Perfect 4th, Perfect 5th),
Detune (25 cents MAX), Level adiust-
ment

Select (OFF, OSC1, 0302, Both),
Mode (UP/DOWN), Time, Intensity

Level adjustment (White noise)

Cutoff frequency, Resonance,
Keyboard track (0,1/4, 1/2, 1), EG
polarity (Itx ,\,_/ ), EG intensity

Attack time, Decay time, Breakpoint
level, Slope time, Sustain level, Release
time, Velocity sens

Attack time, Decay time, Breakpoint
level, Slope time, Sustain level, Release
time, Velocity sens

Waveform ( /\, I\ , /l .J-L ).
Frequency, Delay time, OSC intensity,
VCF intensity

Max. OSC bend (i1 octave), VCF
bend ON/OFF

Portamento time

Time (approx. 4 ~ 512ms), Factor
(x05 ~ 1.0), Feedback level,
Modulation frequency (max. 10HZ),
Modulation intensity, Effect level

OSC MG, VCF, VCA

POLY 1, POLY 2, UNISON 1,
UNISON 2

Send/receive channel (ch 1 ~ 16),
ENABLE (NOTE DATA/ALL), ONINI
(ON/OFF), Arpeggio clock

0 Volume
0 Tune

0 Joystick

o Arpeggiator

o Programmer

0 Display

0 Tape interface

0 Input jacks

0 Output jacks

0 Tape switch
0 Write switch
o MIDI jacks

0 Power
consumption

0 Power supply
0 Weight
0 Dimensions

0 Accessories

(0 ~ max.)
:50 cents

X axis (OSC bend, VCF bend), + Y
axis (OSC modulation), -Y axis

(VCF modulation) '

ON/OFF, Assign (UP/DOWN Mode or
ASSIGNAB LE mode), Octave (1, 2,
full), Latch [ON/OFF), Speed control
slider (Arpeggio tempo: = approx. 20
~ 250)

Value (edit slider, UP/DOWN switchv
es), PROGRAM/PARAMETER
switches, Number select buttons (1 ~

8), WRITE switch, BANK HOLD
switch

Program number, Parameter number,
Parameter value

Save, Load, Verify, Cancel

FROM TAPE (HIGH/LOW), DAMPER
(1, GND), PORTAMENTO (1, GND),
Program UP (1, GNDI

Output (R, L/MONO, HIGH/LOW),
PHONES, TO TAPE

ENABLE/DISABLE
ENABLE/DISABLE
IN, OUT, TH RU

31W

Local voltage
10.9kg
998(W) x 338(0) x 101 (H)mm

AC power cord, Connection cord,
Data cassette, Program card

Page 32

5. Main circuit explanation

1) Keyboard scanning

The CPU outputs 3-bit addresses in the range A0~A2 which
are decoded by the address decoder HC138 (IC25, IC28).
The output of this decoder goes through connector CN10
(first contact) and CN11 (second contact) to the keyboard
matrix for scanning.

Keyboard matrix output goes from connector CNS through
the inverting octal buffer HC240 (l016 HD specification)
to be passed to the data bus DOND7.

2) Key on/off data and velocity data

Velocity data is computed using the CPU timer to measure
the time from when the key contact leaves the first contact
until it reaches the second contact.

KEY ON data is generated when the key contact reaches
the second contact. Key off data is generated when the
first contact is reached after leaving the second contact.

3) After Touch data

The ESK-901 keyboard's after touch unit (sandwich of
metal plate, conductive rubber, and metal plate) produces
impedance variations which KLM-759 detects as analog
voltages over the range of 0V~3.5V.

The voltage passes through the multiplexer 4051 (ICE)
to the CPU where, via a DAC, it changes the control voltage
for the effect.

4) DWGS system

This board contains the DWGS basic system. The purpose
of this system is to get pitch and waveform data from the
CPU bus and output a cyclic (repetitive) waveform of con
stant amplitude.

Oscillator operation

The PAI (phase angle increment) value and PAR (phase

angle register) value are added and the result is stored again

' in the PAR. The PAR value is used as the wave table ad-
dress. The wave table stores different harmonic configura-
tion data for each octave on the keyboard.

IC47 (MBG4H129) performs the processing needed to use

the PAR value as the wave table address.

Finally, data read from the wave table is converted to an

analog waveform by a D/A converter.

Time division multiplexing enables dual oscillator G-voice

sound source capability.

Maximum simultaneous output of this system is 8 voices

x 2 oscillators.

NotezGiven a sampling frequency of 50 kHz, PAl data
N = 2 x f/SO x 103 (where f is the pitch frequency)
is rounded to an integer value for N and converted
to a hexadecimal number.

The main LSI chips are the CMOS gate array I047 (MB-
64H129) and lC60 (M362H133), the wave-table 256K
mask ROM lC45 and IC46 (HN613256), the ten TTL 64-
bit RAM chips for PAI & PAR (IC48~ICE7; $189), the
8-bit D/A converter IC42 (DAG-08), decoder chips lCSO,
IC59 (L8244), KLM-662 lC16 (L8175), IC14, IC15
(LS138), as well as S/H analog switches (IC17~ICZO; 4066)
and OP AMPS (IC21~I025; 072).

ICSO (M362H133) is a 64-pin LSI with about 800 gates
handling major aspects of the system including the CPU
interface, timing generation, and adder.

CPU BUS

______ 260
(MEB2H133)

-CPU INTERFACE

74LSlB9 X 10
IC4B~IC§7

...... ICES (62H133l

I047

(64H29)
34K ROM

I045, I645

------ DAG-08

-- HCISB+40€6+072

I5 050! LLATOH OUTPUT

, --35-