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Casio CTK-450 Service Manual

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CTK-450
CTK-450
ELECTRONIC KEYBOARD

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  Summary of Contents for Casio CTK-450

  • Page 1 (with price) CTK-450 CTK-450 ELECTRONIC KEYBOARD...
  • Page 2: Table Of Contents

    CONTENTS SPECIFICATIONS ......... . . 1 DISASSEMBLE INSTRUCTIONS .
  • Page 3: Specifications

    SPECIFICATIONS General Number of Keys: Polyphonic: 16-note Preset Tones: Auto-Rhythms: Auto-Accompaniment: CASIO Chord/Fingered Auto-Play Tunes: Songs: 32 (Melody ON/OFF) Free Sessions: 32 Terminals: PHONE/OUTPUT Jack [Output Impedance: 40 , Output Voltage: 3.5V(rms)MAX], AC Adaptor Jack (DC9V) Built-In Speakers: 10 cm dia. 1.5W Input Rating: 1 pec.
  • Page 4: Disassemble Instructions

    DISASSEMBLE INSTRUCTIONS Note: The keyboard PCBs are fixed to the case by springy clicks instead of by screws. To disassemble keyboard PCBs 1. Using gentle force, press a click to release the PCB from the click. A click can be caught in the slit behind of it, or can be deformed if too much force is used. When a click is caught in the slit, return it to original position with a tweezers.
  • Page 5: Block Diagram

    BLOCK DIAGRAM Reset IC S-8053ANO Output Jack KO0~KO14 Main Volume Amplifier Filter LA4598 T4/T5 Speaker Mute Circuit M5218APR KI0~KI7 MSM6567-15 Keyboard VCC +9V VDD +5V AVDD +5V LEDX6 (APO) Power Supply Circuit T1/T2/T3 Switches Oscillator...
  • Page 6: Circuit Description

    CIRCUIT DESCRIPTION Key and Switch Matrix / t r - l l i Nomenclature of Keys F#3 G#3 A#3 C#4 D#4 F#4 G#4 A#4 C#5 D#5 F#5 G#5 A#5 G2 A2 C2 D2 C3 D3 G3 A3 B3 C4 D4 E4 B4 C5 D5 —...
  • Page 7: Cpu (Msm6567-15)

    CPU (MSM6567-15) Containing sound data ROM and DAC (Digital to Analog Convertor), the CPU provides sound waveform in accordance with the pressed key and the selected tone. The following table shows pin function of the LSI. Pin No. Terminal In/Out Function LEDY0 Not used.
  • Page 8: Filter Block

    Filter Block Since the sound signal from the CPU is a stepped waveform, the filter block is added to smooth the waveform. MSM6567-15 To mute circuit Mute Circuit The mute circuit removes noise from the sound signal just before the signal fades away. The circuit detects amplitude of the decaying sound signal by amplifing it by 1000 times, and transistor T6 flows the signal into the ground when the amplitude decays almost zero.
  • Page 9: Power Amplifier (La4598)

    Power Amplifier (LA4598) LA4598 is a 2-channel power amplifier with stand-by switch. The following table shows the pin functiion of the power amplifier. Pin No. Terminal In/Out Function Power GND Ground (0V) source Ch1 B.S. Terminal for bootstrap capacitor Ch1 OUT Channel 1 output +9V source Ch1 N.F.
  • Page 10: Power Supply Circuit

    Power Supply Circuit The power supply circuit generates three voltages - VDD (+6.0V) for the CPU and the reset IC, AVDD (+6.0V) for the analog circuit, and VCC1 (+8.6V) for the pilot lamp and the power amplifier. When turning power on, the 100 capacitor makes transistor T2 on first then the CPU provides transistor T2 "High"...
  • Page 11: Schematic Diagrams

    SCHEMATIC DIAGRAMS M6110K-KY1M, KY2M — 9 —...
  • Page 12: Pcb View And Major Waveforms

    PCB VIEW AND MAJOR WAVEFORMS — 10 —...
  • Page 13: M5508-Ma1M

    M5508-MA1M +0.5 - 2.7 — 11 —...
  • Page 14: Exploded View

    — 12 —...
  • Page 15: Ic And Transistor Lead Identifications

    IC AND TRANSISTOR LEAD IDENTIFICATIONS LA4598 S-8053ANO M5218APR 2SA854SR 2SD2008Q,R 2SC3112B 2SC1740SQ 2SD1468SR — 9 — — 13 —...
  • Page 16: Parts List

    PARTS LIST CTK-450 Notes: 1. Prices and specifications are subject to change with- out prior notice. 2. As for spare parts order and supply, refer to the "GUIDEBOOK for Spare parts Supply", published separately. 3. The numbers in item column correspond to the same...
  • Page 17 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price PCB Ass'y M5508-MA1M 2011 6979 LSI MSM6567-15GS-K-109 1,060 2105 2219 IC S-8053ANO 2114 1799 IC M5218APR 2114 2891 IC LA4598 2220 1387 Transistor 2SC1740SQ-TP-T 2 10 2250 0168 Transistor 2SA854-SR-TP-T 1 10 2252 0168 Transistor...
  • Page 18 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price 2819 0395 Ceramic capacitor RT-HE40TKSL100F-T 2 20 2830 6436 Mylar capacitor AMZV-473K50-T 2 20 2845 3220 Ferrite beads EXC-ELDR35V-T 1 10 3025 0658 EMI filter ELK-AH103EB 3 10 3501 7049 DC jack HEC2305-01-330 3612 0711 Miniature jack YKB21-5101...
  • Page 19 MA0200941A...