Korg EX-800 User manual

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KORG
KORG PROGRAMMABLE POLYPHONIC SYNTHE MODULES
H
CONTENTS
1. SPECIFICATIONS 1
2. MIDI IMPLEMENTATION 2
3. STRUCTURAL DIAGRAM 5
4. BLOCK DIAGRAM 7
5. CIRCUIT DIAGRAM .' 8
6. PC BOARD 11
7. CIRCUIT DESCRIPTIONS 14
8. TROUBLESHOOTING TABLE 16
9. CHECK AND ADJUSTMENT PROCEDURE 17
10. PARTS LIST 19
II
KEIO ELECTRONIC LABORATORY CORPORATION
TOKYO/JAPAN
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1. SPECIFICATIONS
• Voice 8 Voice (WHOLE mode)
4 Voice (DOUBLE mode)
• DCO 1 Octave (LOW, MID, HIGH), Waveform
( K.n), 16' 8' 4' 2' (ON/OFF)
Level (0 - 31)
• DCO 2 Octave (LOW, MID, HIGH), Waveform
( K, n). 16' 8' 4' 2' (ON/OFF)
Level adjustment, Interval (0 - 12
semitones), Detune (-20 cent MAX)
• DCO Mode (WHOLE, DOUBLE)
• Noise Level (0 - 15) (White noise)
• VCF Cutoff Frequency (0 • 99), Resonance
(0 - 15), Keyboard Track (OFF, HALF,
FULL), EG Intensity (0 - 15) EG
Polarity (\y, /S), Trigger mode (for
DEG 3 only) (SINGLE, MULTI)
• Chorus ON/OFF
• DEG 1 Attack time, Decay time, Break Point
(FOR DCO 1) level, Slope time, Sustain level,
Release time (ALL 0 - 31).
• DEG 2 Attack time, Decay time, Break Point
(FOR DCO 2) level, Slope time, Sustain level,
Release time (ALL 0 - 31).
• DEG 3 (FOR Attack time, Decay time, Break Point
VCF & NOISE) level, Slope time, Sustain level,
Release tirne (ALL 0 - 31).
• MG Frequency, Delay time, DCO intensi
ty, VCF intensity (ALL 0 - 15).
• MIDI Receive Channel (1 - 16), Program
Change (ENABLE/DISABLE), Se
quencer Clock (INT, EXT), Bend (IN
TENSITY)
• TUNE +/-50 cents
• Key data receiv- Ci~Ce/61 keys (36-96 at MIDI)
able range
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2. MIDI IMPLEMENTATION
n
a
1 Transmission data
Transmittable data consist of system exclusive messages
only. These are used for the computer dump function.
System Exclusive Messages
NOTE:
1. Data error message is sent if there is a check sum er
ror during memory load. Error message: (F0h, 42h,
21 h. 01 h, 20h, F7h)
2. The request sent by the computer must be: F0h, 42h,
21 h, 01 h, 10h, F7h (where V means hexadecimal).
Memory data is then output in the order: F0h, 42h,
21 h, 01 h, memory data check sum, F7h —
2 Reception data
Channel Messages
NOTE:
1. CHANNEL NUMBER:
nnnn = 0H-FH (ch1 y-ch16)
2. NOTE NUMBER:
kkkkkkk = 36~96
If received data is outside of this range, it will be trans
posed to nearest note of the same name.
3. Negative numbers are ignored.
4. OMNI ON/OFF is always interpreted as being accom
panied by POLY-ON.
Separate POLY-ON or MONO-ON messages are
ignored.
5. ppppppp = 0~127 (PROGRAM NUMBER)
However, if number exceeds 63 then subtract 64 to find
value as interpreted.
Example:
74 = 10
64 = 0
6. VOLUME CONTROL:
vvvvvvv = 7Fm is the loudest volume.
decreases as value approaches OOh.
System Real Time Messages
Volume
CAUTION:
ACTIVE SENSING
If FEh (STATUS 11111110) is ever received, then another
FEh or other MIDI data must be received every 300ms,
otherwise the voices will be turned off. If FEh is never
received then operation will continue as usual.
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System Exclusive Messages
NOTE:
1. EX-800 begins RAM data dump about 300msec after
it receives the final F7Hin the RAM data request above.
2. £" (One word of RAM data)n Least significant 8 bits
"" are used for check sum.
3. Send data to EX-800 MIDI IN in the order:
F0h, 42h, 21h, 01h, memory data check sum, F7h, In
ternal.
RAM Data Chart
NOTE:
1. SEQ DATA is as shown below.
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EXAMPLE:
DC
DATA: B4h, 02h, B5h, 02h, 01h, 01h, B7h, B9h, 34h, 37h,
BCh, 02h, 02h, 02h, 02h, 02h, 01 h, 01 h, OOh
2. CHORD MEMORY
0 knknkokaknknkn: KEY DATA
00000 000: END
3. Important: EX-800 does not use undefined data except
for check sum.
Panel Control
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Program Parameter per ONE note
y////////
'UNDEFINED
////////A
PRAMETER WITH ^EXCEEDS BYTE UNIT.
NO SPACE BETWEEN NOTES
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CO
33
|
33
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TCS-5350-01-1011
220ft $ DTC114Nx2
0.0022
CD
KLM-596
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CD
5
O
O
SWITCH
MATRIX
O TO TAPE
FROM TAPE
TAPE
INTERFACE
LINE OUT
L OUT
O R/MIX
OUT
PHONE
OUT
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CJ1
CD
00
f
6-2A
C18
Atype;2SA1175
C type ; 2SC2785
1S2473or 1S1555
NE570or NE571
_ , 6-5A 6CH0RUS SW
002 ,
LFJMC To i€r-l3A 6-13 8.
31 KLM-596< » • ,
r 7 i6-12A 6-12B m
PHONE OUT L
6-ITA 7-2B, 7-2C. 7-lC 6-1OB
V^6oh J?m6-119
Till sep production
From oct production
L J
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O)
7-6B#
7-6C
# 7-3B
to
3-1A#-
2-4C
7-7B#
7-7C
7-4C
• 7-4B
<CW
VR1
10KB
K12261001
7-2C
7-2B0—• '
CW
7-5C
#7-5B
VR2
TUNE
10KB
3-2A0
k3-3C
KLM-596
EWH-14Ax2
VR3
SPEED
100KC
SW 3-4A*-
COLUMN
To 3-5A#-
KLM-596
3-5C
3-6C
3-7AS
k3-7C
7-1C
#7-1B
3-8C
POWER SW
o
4 -1A
SW1 1
,D5
,04
■03
,010
,09
,D8
,D7
SW LINE
1-9C
—• • 3-9A
,015
,D14
cr^
D11
SW2 2
SW5 3
SW4 4
SW5 5
SW6 6
SW7 7
SW8 8
3-10C
#—03-1OA
.D2
SW9 HOLD
SW10 UP
SW11 DOWN
SW12 PROG/PARA
SW13 WRITE
3-11C
* 3-11A
SW14 START
/STOP
4-14C
4 -9A .
4-14A>/
LED 3US
FromKLM-596
LED CONT
From KLM-596
SW15 STEP
TM1-0lxl5
Dl : 1S
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6. PC BOARD
KLM-596
O
m
X
CD
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o
zr
o
CD
—K
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CD
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CD
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ICI
IC23
Rl 6CL, T" c R93 ,C73 . «C6
- 0l74>-^-n*i "Pa R96 ' ' . PROGRAM STEPUP
I 40H74 tJzt:—oqTO doVO, »o
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KLM-598
RI8
1
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J27
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aavw 03X03H3
t?/WS C/V\S B/WS
9031 SQ31
SIO
8d
VkMS |Q
sa so ^a
CO 20
HlH
ClQ
310
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7. CIRCUIT DESCRIPTIONS
MAIN CIRCUIT DESCRIPTIONS
The EX-800 is intended to be an expander unit for connec
tion to synthesizers, sequencers, or other equipment that
has a MIDI output. It is essentially the POLY-800 without a
keybord. However, there are some differences in the MIDI
functions, as detailed in the MIDI IMPLEMENTATION
notes.
The memory backup system rs also different. The EX-800
employs an internal lithium battery to protect data in its
memory. The life of this battery is about five years and it
should be replaced after that time has elapsed.
For check and adjustment of the EX-800 please refer to the
POLY-800 service manual.
Below are simple descriptions of each circuit block.
Refer to circuit diagram for number.
1) Tape interface input circuit:
Consists of amplifier and comparator. When command is
executed, data on this line is input to the CPU accumu
lator's 7th bit.
2) CPU:
A CMOS 8-bit microprocessor IG24 (80C85) featuring low
power consumption. Virtually all POLY-800 functions are
handled by this CPU.
3) Reset circuit:
IC40 (PST518) is a 3-pin IC used for reset. It generates an
initial reset voltage of about 4.2V.
4) Sequencer tempo clock oscillator circuit
The tempo circuit includes IC28 (TC40H074) and 1/2 of
IC36(whichis1/2ofaTL072).
The tempo control is connected to CN2 pin 1 providing
10Hz±20% at the knob's 0 position and 100Hz±20% at the
10 position for CPU interrupts. If this circuit fails, then
there will be no sound from the sequencer section.
5) Interrupt oscillator circuit:
This oscillator cycle is used for the EG, MG, LED displays,
and S/H time division processing. Oscillator frequency is
2400Hz-N-3600Hz. Interrupt order is by priority. If this
circuit fails, EG operation and LED indication may become
erratic.
6) Address Decoder:
TTL circuit decodes addresses for RAM and other ICs.
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7) ROM (8192 words x 8bit PROM)
8) RAM (2048 words x 8bit static RAM)
9) Address latch:
IC latches according to CPU ALE (Address Latch Enable)
terminal output signal since CPU uses address LSB 8bits
together with data bus 8bit input.
10) Peripheral I/O:
PA, PB, and PC ports are all used for output. The internal
timer is used for the interface IC26 (63B50) reference clock.
The CPU 3MHz clock frequency is divided by 6 to obtain
500kHz. RAM is used for the program working area.
11) LED display drive circuit:
IC30 (BA618) and IC31 (M54513) form a 6 x 8 matrix for
time sharing indication by the panel's 7-segment LED
display.
12) 8-bit D/A converter:
Uses CMOS noninverting buffer IC32(HD 14050or "4050"),
and BR9 (RKM10L253F or "BR9") a 10-pin (R=25kohm)
R-2R ladder resistor in D/A converter with output of 0V ^
4V.
13) External DC power supply ripple filter:
Diode D2 is used to protect the circuit in case of reverse AC
adapter polarity.
14) LED display power supply:
Circuit is designed so that LEDs become dim when battery
voltage drops below rated level, (about 6V)
15) +5V power supply:
This circuit design is employed because it maintains normal
operation up until just before the batteries drop below
rated voltage of Volts (about 6V)
16) -5V power supply:
A type of DC-DC converter.
18) A/D converter comparator.
19) Master oscillator:
Varactor VC1 and coil KL-003 are used in the oscillator
circuit. This generates a frequency of about 2MHz at the
tune knob's center position. This is divided down (to about
1MHz) to supply the TG. (CL1, CL2)
Bend and vibrato control voltages are D/A converted by
IC35 (3404) and applied to the oscillator.
20) EG S/H circuit:
EG values calculated by the CPU are output by time sharing
and input to the TG.
LED diodes for each voice are there to smooth the stepped
transition.
21) Keyboard panel switch input circuit:
A 9 x 8 matrix is formed by DTC5, IC34 (TC40H138), and
IC33 (TC40H240). This handles keyboard and panel switch
outputs as well as output from the comparator in circuit
diagram (18).
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22) Detune circuit:
Lowers frequency by thinning out clock pulses.
23) Tape interface output circuit.
24) CV circuit:
Performs time division output and S/H on CV for VCF and
master oscillator.
25) 6-bit latch circuit:
A 6-bit control output circuit with 2 bits for detune, 2 bits
for DCO waveform switching, 1 bit for A/D converter, X-Y
switching, and 1 bit for noise gate control.
26) 6-bit latch circuit:
A 6-bit control output circuit with 5 bits for S/H control
and 1 bit for chorus on/off switching.
27) VCA + VCF circuit:
The IC1 (NJM2069) has three internal VCAs and one
internal 24dB/oct VCF (LPF). SIG1 and SIG2 respectively
receive mixed DC01 and DC02 inputs from the TG;
LEVEL1 and LEVEL2 are control input terminals.
The other VCA is for noise only. The 9pin (VCA LIN IN) is
its control terminal.
MG, EG INT and CUTOFF, KBD TRACK are controlled
separately and input to VCF LOG.
See REFERENCE DATA for details.
31) Waveform synthesis circuit:
Using the TG's various foot outputs (16', 8', 4', and 2'),
this produces 2-waveforms, one by addition on a 1 = 1 = 1 = 1
basis and the other using the ratio 1 = 1/2=1/4=1/8.
The block resistor BR5 (RKC 1/8 B4 33K) is made up of
four 1/8W 33k resistors (1 = 1 = 1 = 1). BR6 (RMO0470) is
10K ohms using R, 2R, 4R, 8R (1 = 1/2=1/4=1/8).
32) TG (Tone Generator):
An IC having eight sets of dividers and VCAs. See
REFERENCE DATA for details.
KLM-598,614
KLM-598 consists of the chorus circuit and headphone amp
circuit. The VCF output signal transits noise gate F1
(2SK381) and is input to compressor IC3 (NE570); then
IC4 (M5224P) detects the envelope.
The clock generator circuit which drives the BBD IC makes
IC7 (M5224P) generate a triangle wave which comparator
IC8 (393) converts to a sawtooth wave with a change of
pitch for a more natural chorus effect.
F2 (2SK381B) at the output is an FET for chorus on/off
switching.
KLM-614 includes the panel section LED display and
switch matrix circuitry.
28) Analog switch circuit:
Performs DCO waveform switching and joystick A/D con
verter input switching.
29) Noise generator.
30) MIDI interface circuit:
This is a standard type MIDI interface circuit employing
the MIDI interface IC26 (ACIA63B50) and high processing
speed photocoupler PC-1. (PC-900)
D22 is used to prevent destruction of the photocoupler
LED in case a reverse voltage is applied. R119 (220 ohm)
and R121 (220 ohm) resistors are for prevention of damage
in case of excessive current.
The circuit is designed to provide a data transmission rate
of 31.25 k baud(±1%).
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8. TROUBLESHOOTING TABLE
The order in which things should be checked naturally coincides with the signal path in the POLY-800. Please refer to this
flow chart to help you pinpoint sources of malfunctions. Remember to save user programs to tape before beginning service
procedures.
No sound or other
malfunction.
Try loading data
from accessory tape.
Check +5V
(No. 15),
-5V (No. 16)
supply voltage {No. 13,
16) for ±5V.
Is tone
generator (IC3) output
correct?
Is waveform ^\ NO
synthesizer circuit (No.31)
output normal?
Is the correct
signal being input at
VCF (IC1)20and21
pins?
Check connector
CN-61 pin. Is VCF
output present?
Check ^
to^see whether EG controL
^signal is being input pro-
Check No. 31
circuit IC,
block resistors.
Check analog
switch circuit
(No. 28).
Check IC 1
(NJM2069).
Replace.
Is EG S/H circuit-^YES
No. 20) getting correct
input?
Replace IC12
(HD14051).
YES
CheckTGIC3
(MSM5232).
Replace if
necessary.
Check master
oscillator cir
cuit (No. 19).
Check KLM-598 compressor/expander
IC(IC3), BBDIC(IC5),etc.
The problem is probably in this circuit
board.
The problem is in the main board
(KLM-596). Check CPU, I/O, RAM,
ROM, etc. control lines and address
and data buses for problems.
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9. CHECK AND ADJUSTMENT PROCEDURE
ADJUSTMENT PROCEDURE
Use the POLY-800 for check and adjustment of the EX-800.
Connections are as shown here. Use a 5-pin DIN cable less
than 15m long for connection.
Note: The EX-800 MIDI OUT terminal is for memory
dump to a personal computer (via a MIDI interface).
Caution: This product has been thoroughly adjusted at the
factory before shipment. Therefore do not adjust anything
other than those VRs required for servicing.
BEFORE making any calibration adjustments, Be sure test
data is loaded into EX-800.
The following setting chart shows the program data used
for service testing. After inputting the data, save it on tape
for future time saving convenience.
PROGRAM no. 11 (noise level):
PROGRAM no. 12 (master oscillator):
1. Power supply circuit (KLM-596, circuit no. 15):
Be sure that the specified AC adapter is being used: 9V,
300mA,
1) +5V check and adjustment:
Use DVM (digital voltmeter) to check KLM-596 connector
CN6 Pin 6 and confirm +5V *(±0.005V). Adjust VR1 if
necessary.
2) -5V check:
Use DVM to check KLM-596 connector CN6 Pin 8 and
confirm -5V (within -4.7V - -5.7V)
2. D/A converter check and adjustment (KLM-596, circuit
No. 12):
1) Select program No.12
2) Set joystick bend control of POLY-800 at center posi
tion: BEND INT to 10
3) Connect DVM to KLM-596 IC10 (TL062) Pin 7 and
confirm 2.001V ±0.005V. Adjust VR4 if necessary.
Also confirm:
3.984V ±0.005V for an upward pitch bend and
0.024V ±0.005V for a downward pitch bend.
Note: Adjustment is easiest in the joystick circuit although
the idea is to obtain a 4V output from IC 38 (TL062) by
adjusting the D/A converter when IC 81C55 port A output
is all high.
3. Noise level check and adjustment:
1) Select program no. 11.
2) Depress any single key of POLY-800.
3) Connect oscilloscope to KLM-596 CN6A 1 pin and con
firm noise level of 0.3Vp-p (± 20%).
4) Adjust VR3 if necessary.
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4. Master oscillator check and adjustment:
Set tune knob to center and bend intensity to maximum.
Connect AT-12 to line out jack.
1) Select program no. 12.
2) Depress C3 key of POLY-800.
3) Confirm AT-12 indication of -1 OCT, C, Ocent. If nec
essary, adjust by turning KL-003 coil.
4) Next, push joystick to maximum upward pitch bend
position and confirm AT-12 reading of —1 OCT, G, +35
cents. Adjust KLM-601 VR2 if necessary.
5) At maximum joystick downward pitch bend AT-12 indi
cation should be -2 OCT, F, -35 cents. Adjust KLM-601
VR1 if necessary.
VR3 is a semi-fixed resistor to fix range of tune VR on
front panel.
Confirm +40 ~ +70 cents when tune VR is at # max
position.
Confirm -40 ~ -70 cents when tune VR is at b max
position.
If necessary, Adjust VR3.
5. Cutoff check and adjustment:
1) Select program No. 13.
2) Play C3 key of POLY-800
3) Connect oscilloscope to CN6A pin 1 and observe wave
form as in figure 1.
4) Adjust VR2 to obtain maximum waveform amplitude.
6. Resonance check and adjustment:
1) Select program no. 14.
2) Play C3 key of POLY-800.
3) Confirm that waveform is as shown in figure 2.
4) Adjust VR5 if necessary to prevent oscillation or to cor
rect waveform deviation from figure 2 example.
1.5msec (±20%)
0.1 V/div, 1msec/div
Fig. 2
Fig. 1
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10. PARTS LIST
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