ELECTRONIC KEYBOARD
AP-20
(with price)
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CONTENTS
Safety Notice ...................................................................................... 2
Specifications .................................................................................... 3
Block Diagram ................................................................................... 4
PCB Layout ........................................................................................ 5
Disassembly Instructions ................................................................. 6
Circuit Description .......................................................................... 10
Major Waveforms ............................................................................. 12
Troubleshooting .............................................................................. 13
Wiring Diagram ................................................................................ 17
Exploded View ................................................................................. 18
Parts List .......................................................................................... 21
Schematic Diagrams ....................................................................... 23
SAFETY NOTICE
CAUTION!
Danger of explosion if battery is incorrectly replaced.
Replace only with the same of equivalent type recommended
by the appliance manufacturer.Discard used batteries
according to manufacturer's instructions.
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SPECIFICATIONS
GENERAL
Number of keys
88
Polyphonic:
32-note
Preset tones:
10, PIANO 1, PIANO 2, ELEC. PIANO, HARPSICHORD, VIBRAPHONE,
PIPE ORGAN, STRINGS, CHOIR, W.BASS (Lower tone only),
E.BASS (Lower tone only)
Layer/Split function
Key transpose:
F#-C-F
Keyboard controls:
Tuning curve, Baroque pitch
Temperaments:
Equal Temperament, Kirnberger III, Werckmeister, Mean-Tone,
Just Intonation (Minor/Major), Pythagorean System
Effects:
Reverb (Room, Stage, Hall 1, Hall 2)/Chorus/Tremolo/Brilliance
Demo tunes:
8,
1. Polonaise "Héroïque" (F.F. Chopin)
2. Frühlingslied Op. 62-6 (F. Mendelssohn)
3. CASIO original
4. Harmonious blacksmith (G.F. Händel)
5. CASIO original
6. Jesus, Bleibet Meine Freude (J.S. Bach)
7. CASIO original
8. CASIO original
Memory:
Number of Songs:
2 (A and B)
System:
Real-time recording
Memory Capacity:
Approximately 3,000 notes total
Memory Backup Battery:
Built-in lithium battery
Battery Life: Approximately 5 years
Pedals:
Soft, Sostenuto, Damper
Tuning control:
440Hz
±50 cents
Built-In Speakers:
16 cm dia. x 2 (Output: approx. 20 W + 20 W)
MIDI:
16-channel, multi-timbral reception
Terminals:
PHONES 1 and 2, MIDI (IN/OUT/THRU), LINE OUT L and R (Output Imped-
ance: 10 K
; Output Voltage: 2 V, RMS, max.), LINE IN R and L (Input Imped-
ance: 20 K
, Input sensitivity: 200 mV)
Power source:
120V (for U.S.A.),
120V, 220V, 230V and 240V (for other countries)
Power consumption:
65W (with 120V AC), 55W (with 220V, 230V and 240V AC)
Dimensions (HWD):
Without stand: 185
× 1340 × 520 mm (7-5/16 × 52-13/16 × 20-1/2 inches)
With stand:
820
× 1360 × 550 mm (32-5/16 × 53-9/16 × 21-11/16 inches)
Weight:
Without stand: 35.5 kg (78.3 lbs)/38.5 kg (84.0 lbs)
With stand:
45.5 kg (100.4 lbs)/48.5 kg (106.1 lbs)
Note: There are two models of AP-20, one has a keyboard cover, the other has no keyboard cover.
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DSP
HG51B155FD
RAM
256K
HM62256BLP-10
ROM
1M
MX23C1010PC-
12CA25
CPU
HD6435328RC13F
PEDAL
MIDI
IN
OUT
ROM
8M + 16M
HN62418PD25
HN624116D44
RAM
256K
× 2
HM65256BLSP-
10
× 2
Keyboard
Controller
HG52E35P
Switch & LED
Controller
µPD65005GF-419
D/A Converter
µPD6376CX
D/A Converter
µPD6376CX
Filter
Mixer, Mute Circuit
T6, T7, T10, T11
Power Amp.
STK4132MK
RA0 ~ 19
RD0 ~ 15
EA0 ~ 14
ED0 ~ 15
A0 ~ 3
A0 ~ 14
D0 ~ 7
KC0 ~ 4
KI0 ~ 3
L1 ~ 9
LA ~ J
LEDs
Switches
Keyboard
KC0 ~ 7
FI0 ~ 10
SI0 ~ 10
Main
Volume
Voltage
Regulator
M5F78M12L
×2
M527BL05
T8,
T9
AVCC
AVDD
AVFF
VDD
+12V
+5V
12V
+5V
SOLM, SOLP
BDK, WOK1, SORM, SORP
Power
Switch
Power
Transformer
T101
Reset IC
MB3771P
RST
MUTE
BRILLIANCE
MIDI
MIDO
SF
SS
DP
Filter
LINE IN
P70 ~
P77
P12 ~
P14
BLOCK DIAGRAM
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POWER
VOLUME
MIN
MAX
HALL 2
BRILLIANCE
MELLOW
BRIGHT
CONTROL
PIANO 1
TONE
PIANO 2
E.PIANO
HARPSICHORD
PIPE ORGAN
STRINGS
CHOIR
VIBRAPHONE
W.BASS
E.BASS
LOWER TONE
REVERB
HALL 1
STAGE
ROOM
TREMOLO
CHORUS
SONG A
MEMORY
SONG B
RECORD
START/
STOP
TUNE
DEMO
OFF
ON
MA2M
MA1M
PS1
CN2M
CN1M
CN3M
IF1M
MA4M MA5M
TP10-KY1M
TP10-KY2M
PCB LAYOUT
Note: IF1M PCB is a terminal board for the keyboard PCBs, and included in the main PCB.
PCB
Main PCB
Jack PCBs
Console PCBs
Power PCB
JCM433-
MA1M
MA2M
MA4M
MA5M
CN1M
CN2M
CN3M
PS1
Components
CPU, DSP, Sound Source ROM Working storage
RAM, Effect RAM Reset IC, DAC, Filter, Key con-
troller, Power amp, Power supply circuit
LINE IN/OUT jack, MIDI jacks
Phone jacks
Power indicator
Gate array (Button controller/LED driver), LEDs,
Buttons
Main Volume, Brilliance volume
Tune Buttons, Demo button
Fuse, Noise filter