Yamaha PORTATONE KB-280 Service Manual page 47

A B C
KB-280 OVERALL CIRCUIT DIAGRAM (AM, DMLCD, MIDI, PB, PNL, PNR, TWL, TWR, 61H, 61L)
1
DMLCD
2
LCD
DRIVER
3
XX
4
SYSTEM RESET
5
CPU
(USB)
XX
6
7
to K-5
B
8
XX
RH5RZ25CA-T1-F (X3679A00) BA33BC0FP (X5889A00)
REGULATOR +2.5V REGULATOR +3.3V
DMLCD: IC103 DMLCD: IC102
9
2
1
2 1
3
1. GND 1. INPUT
3
2. INPUT 2. GND
3. OUTPUT 3. OUTPUT
BA60BC0T (X6980A00)
RH5RZ50CA-T1-F (X6959A00)
REGULATOR +6V
REGULATOR +5V
AM: IC151
DMLCD: IC101
10
1
2
3 1. GND
1: INPUT
2. INPUT
1
2: GND
2
3. OUTPUT 3 3: OUTPUT
DTC123JKA (VY677600)
DIGITAL TRANSISTOR
DMLCD: TR705
3
2
1
R1
OUT
IN
1: GND
R2
11 GND 2: IN
IN OUT 3: OUT
GND
12
KB-280
A B C
D E F G
ROM 128M
PROG./WAVE
XX
DRAM 4M
CPU
(SWL01T)
OR
ADC
OP AMP
DAC
XX
A
OP AMP
to J-2
D E F G
H I J
XX
XX
A
to E-8
XX
XX
XX
XX
XX
XX
XX
FLASH ROM 4M
XX
REGULATOR +5V
REGULATOR +3.3V
POWER SUPPLY
REGULATOR +2.5V
DECODER DECODER
xx
: Ceramic Capacitor
: Mylar Capacitor
61H
: Semiconductive Ceramic Capacitor
(C4~C6)
: Metal Film Resistor
: Flame Proof C.Resistor
XX : Not installed
Note1 : See parts list for details of circuit board component parts.
Note2 : The large numbers with function are indicated the first digit
of the part reference number.
WARNING
Components having special characteristics are marked
replaced with parts having specifications equal to those originally installed.
28CC1-8822437
H I J
K L M
PNR
(PN 1/6)
XX
TRAD.ACD FR.HORN
YANGQIN
VIVES BRASSECT
xx
DIZI1 STRINGS HARP
XX
SUONA1 VIOLIN SQUARELD
CLASSGTR
ERHUENS SWEETFLT
GRANDPNO CLARINET ACO.BASS
HARPSI. OBOE SFXKIT1
CHARCHORG SWEETTP
28CC1-2001002847 1
PNR (PN 3/6)
B
to B-8
28CC1-2001002847 1
MIDI
XX
SUSTAIN-PEDAL
IN OUT
XX
MIDI
(AMJK 2/6)
EXPRESSION
BYPASS CAPACITORS
28CC1-2001002838 1
AM (AMJK 1/6)
REGULATOR +6V
and must be
AM
61L
(AMJK 4/6)
(C1~B3)
XX
MASTER
VOLUME
28CC1-2001002844
28CC1-8822436
K L M
N O P Q
KB-280
PNL (PN 2/6)
LUOGU METRO4/4
ROCK
28CC1-2001002847 1
PNL (PN 4/6)
PB (AMJK 6/6)
PORTAMENTO
PITCH BEND
XX
28CC1-2001002844
28CC1-2001002847 1
SPEAKER R
WOOFER
SPEAKER R
TWEETER
TWR
(PN 5/6,6/6)
28CC1-2001002847 1
AM (AMJK 5/6)
28CC1-2001002844
STANDBY/ON
28CC1-2001002844
POWER SUPPLY
XX
DC IN
XX
POWER AMP 13.5W
PHONES/AUX
XX
SPEAKER L
TWEETER
TWL
(PN 5/6,6/6)
28CC1-2001002847 1
SPEAKER L
WOOFER
28CC1-2001002844
KB-280
N O P Q
1
2
3
4
5
6
7
8
9
10
11
12