Casio AP-20 Service Manual
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Casio AP-20 Service Manual

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AP-20
ELECTRONIC KEYBOARD

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Summary of Contents for Casio AP-20

  • Page 1 (with price) AP-20 ELECTRONIC KEYBOARD...

  • Page 2: Table Of Contents

    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 ...............

  • Page 3: Specifications

    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. — 3 —...

  • Page 4: Block Diagram

    BLOCK DIAGRAM Keyboard MIDI KC0 ~ 7 P70 ~ Keyboard PEDAL Controller MIDI MIDO HG52E35P FI0 ~ 10 P12 ~ SI0 ~ 10 Switches BRILLIANCE KC0 ~ 4 Switch & LED HD6435328RC13F Controller KI0 ~ 3 µPD65005GF-419 L1 ~ 9 LEDs LA ~ J D0 ~ 7...

  • Page 5: Pcb Layout

    PCB LAYOUT MA2M MA1M IF1M HALL 2 REVERB CONTROL VOLUME BRILLIANCE TONE LOWER TONE MEMORY TUNE DEMO HALL 1 TREMOLO CN2M CN1M CN3M START/ STAGE CHORUS MELLOW BRIGHT PIANO 1 PIANO 2 E.PIANO HARPSICHORD VIBRAPHONE PIPE ORGAN STRINGS CHOIR W.BASS E.BASS SONG A SONG B...

  • Page 6: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS 1. Disassembling top board 1-1. Remove 8 screws on the rear. 1-2. Slide the top board towards the rear. The top board will be free from catches on the case. 1-3. Lift the top board. For keyboard-cover model 2.
  • Page 7 3. Disassembling console panel Note: To avoid scratch on the side board, put paper between the console panel and the side board at both ends. 3-1. The console panel is fixed with screws and nuts. Holding the nut, remove the screw. 3-2.
  • Page 8 5. Disassembling keyboard unit 5-1. Remove 6 screws at both ends on the bottom, and a screw at the middle. 5-2. Remove 2 screws at both ends of keyboard unit. 5-3. Disconnect 2 connectors for the keyboard unit from the main PCB. 5-4.
  • Page 9 7. Disassembling keyboard PCBs 7-1. Turn round the keyboard unit to face the PCB 7-2. Disconnect the connector at the middle of keyboard. 7-3. Remove screws on the keyboard PCBs. 8. Replacing the main PCB Note: The main PCB contains a lithium battery for memory back-up. Please remove the jumper before replacing the PCB.

  • Page 10: Circuit Description

    CIRCUIT DESCRIPTION KEYMATRIX Second contact First contact UPD912GF-3BA A0 1 A0 # 1 B0 1 C1 1 C1 # 1 D1 1 D1 # 1 E1 1 A0 2 A0 # 2 B0 2 C1 2 C1 # 2 D1 2 D1 # 2 E1 2 F1 1...
  • Page 11 BUTTON MATRIX Piano2 E. Piano Harpsichord W. Bass Piano1 Strings Choir E. Bass Vibraphone Pipe organ Reverb Song A Song B Record Start/Stop Control Tune up Tune down Demo POWER SUPPLY CIRCUIT The power supply circuit generates four voltages as shown in the following table. Name Voltage For operation of...

  • Page 12: Major Waveforms

    MAJOR WAVEFORMS A 1ms A 20 µs ˜ ˜ ˜ CH1 5V CH2 5V CH3 5V CH1 .2V CH2 .2V 1 Filter output L-ch CC connector pin 1 3 Key scan signal KC0 JA connector pin 5 2 Filter output R-ch CC connector pin 2 4 Key scan signal KC1 JA connector pin 4...

  • Page 13: Troubleshooting

    TROUBLESHOOTING No power Check fuse F101. Is F101 blown up? Replace F101. Check fuses F2, F3, and F4. Are the fuses blown up? Replace F2, F3, and F4. Measure output voltages of the transformer. Are the voltages 40 V AC and 8 V AC? Replace main PCB.
  • Page 14 No sound Does the power indicator light up? Follow "No power" troubleshooting. Check the main volume. Is it OK? Replace main volume. Disconnect JA and JB connectors on the main PCB. Press Demo button. Does the demo tune sound? Replace the main PCB. Replace keyboard PCBs.
  • Page 15 Certain keys do not function Replace the main PCB. Do the keys function? Replace keyboard PCBs. A certain key does not function Clean the contact. Does the key function? Replace the key contact rubber. Does the key function? Replace keyboard PCBs. Does the key function? Replace the main PCB.
  • Page 16 A certain button does not function Replace the console PCBs. Does the button function? Replace MA1M PCB. — 16 —...

  • Page 17: Wiring Diagram

    WIRING DIAGRAM LINE IN LINE OUT MIDI IN OUT THRU JCM433-MA2M JCM433-CN3M JCM433-IF1M TP8/10 KY1 CF-1 JA-1 JA-1 CA-1 CF-1 CA-1 BRILLIANCE CF-2 CF-2 JA-2 JA-2 CA-2 CA-2 AVDDB CF-3 CF-3 JA-3 JA-3 CA-3 CA-3 CF-4 CF-4 JA-4 JA-4 CA-4 CA-4 CF-5 CF-5...

  • Page 18: Exploded View

    EXPLODED VIEW STAND R-10 R-12 R-11 — 18 —...

  • Page 20: Parts List

    PARTS LIST AP-20 Notes: This parts list does not include the cosmetic parts, which parts are marked with item No. "R-X" in the exploded view. Contact our spare parts department if you need these parts for refurbish. Prices and specifications are subject to change with- out prior notice.
  • Page 21 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price Main PCB 2200 4409 Transistor 2SA933-SQ-TP-T 2220 1387 Transistor 2SC1740SQ-TP-T 2240 1050 FET 2SK163N-T 2360 0273 Zener diode RD3.3ESB1-T1-T 2360 1694 Zener diode RD6.2ESB1-T1-T 2011 0455 LSI, RAM HM65256BLSP-10 2011 3325 LSI, DAC UPD6376CX 2011 5194 LSI, Key controller...
  • Page 22 M340318-1 6924 5600 Button set 433 M240304*1 Stand 6924 7050 Pedal box ass'y A190007400 5,120 6924 7060 Screw set for AP-20's stand A190007500 AC cord 3701 0196 AC cord (120V, USA) UC-964-J01 3701 0595 AC cord (230V, Europe) EC-654-E06 3701 0588 AC cord (230V, UK)

  • Page 23: Schematic Diagrams

    SCHEMATIC DIAGRAMS MAIN PCB JCM433-MA1M (1/2) ROM (8M) D/A Converter D/A Converter ROM (16M) (256K) (1M) (256K) (256K) Reset IC Key Controller — 23 —...
  • Page 24 MAIN PCB JCM433-MA1M (2/2), PHONE JACK PCBs JCM433-MA4M, MA5M and POWER PCBs JCM433-PS1 Power Amp. Filter 40V AC 40V AC Power Circuit 8V AC 8V AC — 24 —...
  • Page 25 CONSOLE PCBs JCM433-CN1M, 2M, 3M, and JACK PCB JCM433-MA2M Switch & LED Controller — 25 —...
  • Page 26 INTERFACE PCB JCM433-IF1M — 26 —...
  • Page 27 KEYBOARD PCB TP8/10 KY-1 — 27 —...
  • Page 28 KEYBOARD PCB TP8/10 KY-2 — 28 —...

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