Casio CTK-750 Service Manual
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Casio CTK-750 Service Manual

Casio CTK-750 Service Manual

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CTK-750
CTK-750
ELECTRONIC KEYBOARD

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Summary of Contents for Casio CTK-750

  • Page 1 (with price) CTK-750 CTK-750 ELECTRONIC KEYBOARD...

  • Page 2: Table Of Contents

    CONTENTS Specifications ......... . 1 Replacing the DSP (HG51A115A01FD) .

  • Page 3: Specifications

    Touch Response: On/Off Touch Sensitivity: Light/Middle/Heavy Key Transpose: Range from F# to F by a half-note increment Auto-Rhythms: Tempo Control: 40 to 255 Auto-Accompaniment: CASIO Chord/Fingered/Full-Range Chord Controller: Variation, Fill-In, Intro/Ending Magical Preset Variations: 128; BREAK BEAT MELODYCOMP SHADOW DRUM FREE SESSION...

  • Page 4: Replacing The Dsp (Hg51A115A01Fd)

    Electrical Current Drain with 12V DC: 390 mA ± 20% No Sound Output 1700 mA ± 20% Maximum Volume with white keys D2 to D3 pressed in Synth-Bass-2 tone and in Latin Fusion rhythm at initial setup tempo Volume; maximum, Touch: maximum Line Output Level (Vrms with 47 KΩ...

  • Page 5: Block Diagram

    BLOCK DIAGRAM 7-Segment LEDs LO0 ~ LO4 Keyboard LED driver BA612 Gate Array FI0 ~ FI7 KC0 ~ KO0 ~ KO7 UPD65005C-578 SI0 ~ SI7 LD0 ~ LD7 Buttons D0~D7 KI1 ~ KI7 Key Touch LSI HD6433298A18P HG52E35P A0 ~ A15 POWER A0 ~ A2 Power Switch...

  • Page 6: Circuit Description

    CIRCUIT DESCRIPTION Key Matrix C2 1 C#2 1 D2 1 D#2 1 E2 1 F2 1 F#2 1 G2 1 C2 2 C#2 2 D2 2 D#2 2 E2 2 F2 2 F#2 2 G2 2 G#2 1 A2 1 A#2 1 B2 1 C3 1...
  • Page 7 Nomenclature of Keys F#3 G#3 A#3 F#4 G#4 A#4 C#5 D#5 F#5 G#5 A#5 C#4 D#4 C2 D2 G2 A2 C3 D3 G3 A3 B3 C4 D4 E4 B4 C5 D5 Button Matrix Split Layer Upper 1 Lower 1 Lower 2 Upper 2 Transpose Tune...
  • Page 8 Initial reset When batteries are set or an AC adapter is connected, the reset IC provides a low pulse to the CPU. The CPU then initializes its internal circuit and clears data in the working strage RAM. Power ON reset When the power switch is pressed, the CPU receives a low pulse of POWER signal.
  • Page 9 Gate Array (UPD65005C-578) Functions of the gate array are; (1) To decode chip select signals for the working strage RAM, the DSP and the key touch LSI. (2) To hold the following signals on "Low" during power off. Read/write enable signals for the DSP and the key touch LSI 10MHz clock for the key touch LSI (3) To generate button scan / LED drive signals.
  • Page 10 Digital Signal Processor (HG51A115A01FD) Upon receipt of note numbers and their velocities, the DSP reads sound and velocity data from the sound source ROM in accordance with the selected tone; the DSP can read rhythm data simultaneously when a rythm pattern is selected. Then it provides 16-bit serial signals containing data of the melody, chord, bass, and percussion to the DAC.
  • Page 11 Pin No. Terminal In/Out Function VCC5 +5V source 94, 95 97 ~ 105 EA0 ~ EA14 Address bus for the effect RAM 107,109 110, 112 EWEB Write enable signal output for the effect RAM EOEB Read enable signal output for the effect RAM VCC7 +5V source ECEB...
  • Page 12 DAC (UPD6376CX) UPD6376CX is a two-channel 16-bit Digital to Analog Convertor consisting of resistor string, output amplifier and zero offset circuit. Pin No. Terminal In/Out Function Mode selection terminal. Connected to ground. D.GND Ground (0V) source for internal digital circuit Not used.
  • Page 13 The following table shows the pin functions of the key touch LSI. Pin No. Terminal In/Out Function REQB Interrupt request. Not used. 2, 3 FI10, SI10 Key input signal +5V source CRDB Read enable signal CWRB Write enable signal CCBB Chip select signal 8, 9 T, STBY...
  • Page 14 Power Amplifier (LA4620) The power amplifier is a two-channel balanced amplifier with standby switch. The following figure shows the internal diagram of the amplifier. Internal Diagram of LA4620 Boot11 IN11+ Input Power Pre-drive OUT11 Amp. Amp. Amp. IN11- RL Short PoGND1 Protector IN12-...

  • Page 15: Wiring Diagram

    WIRING DIAGRAM M5712-CN1M Bender Volume LMELO OUT M5172-MA2M RMELO OUT Main Volume RMELO IN LMELO IN A5712-MA1M M615T-KY2M M615T-KY1M — 13 —...

  • Page 16: Major Waveforms

    MAJOR WAVEFORMS — 14 —...
  • Page 17 — 15 —...

  • Page 18: Pcb View And Major Check Points

    PCB VIEW and MAJOR CHECK POINTS 14 15 16 17 9 10 11 — 16 —...

  • Page 19: Schematic Diagrams

    SCHEMATIC DIAGRAMS Main PCB M5712-MA1M 11.4 11.6 11.6 10.9 11.6 10.9 11.8 11.0 14 15 16 17 8 9 10 11 — 17 —...
  • Page 20 Console PCB M5712-CN1M — 18 —...
  • Page 21 Keyboard PCBs M615T-KY1M, KY2M — 19 —...

  • Page 22: Exploded View

    EXPLODED VIEW...

  • Page 23: Ic And Transistor Lead Identification

    IC LEAD IDENTIFICATION AND INTERNAL DIAGRAM UPD6376CX MAIN DAC L.OUT LRCK SUB DAC L.REF LRSEL/RSI SI/LSI SUB DAC R.REF 4/8 fs SEL MAIN DAC R.OUT D.GND A.GND A.VDD N.C. D.VDD S8053ANO 1 OUT M5218APR PC900V TC74HC04AP 1A 1 14 VCC 1Y 2 2A 3 2Y 4...
  • Page 24 Q4: 2SB1274 Q2: 2SD1762E,F Q3, Q5, Q7, Q11/12: 2SC1740SQ Q13: 2SA933SQ Q1/6: 2SB1240Q,R Q14~21: DTA114TS — 22 —...

  • Page 25: Parts List

    PARTS LIST CTK-750 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 26 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price PCB Ass'y M5712-MA1M 2010 4928 LSI HM65256BLP-10 2011 3325 LSI UPD6376CX 2011 5194 LSI HG52E35P 2011 5201 LSI HG51A115A01FD 2,820 2011 5810 LSI UPD43256AC-85L,10L 2011 6867 LSI UPD65005C-578 2011 7196 LSI TC5316200CP-C081 1,230 2011 7203 LSI...
  • Page 27 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price 2802 9231 Electrolytic capacitor 25RE3-2200-S1 2 10 2803 6743 Electrolytic capacitor 50RBP2-R22-T2-T 2 20 2803 6750 Electrolytic capacitor 50RBP2-R33-T2-T 2 20 2803 6757 Electrolytic capacitor 50RBP2-4R7-T2-T 2 20 2805 3061 Electrolytic capacitor 6.3RE2-220-T2-T 1 10 2805 3134 Electrolytic capacitor...
  • Page 28 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price 3637 5220 Ferrite core ZCAT2032-0930 4317 3820 Blank PCB M615T-KY1M M111575-1 6921 8590 PCB ass'y M615T-KY1M M111608*1 6921 9460 Sponge 60x400 M412219-1 1 10 PCB Ass'y M615T-KY2M 2301 0101 Diode 1S2473T-77-T 58 20 3501 7602 8P connector MHTRASKD...
  • Page 29 FOB Japan Item Code No. Parts Name Specification N.R.Yen Unit Price 27-1 6902 6140 Battery spring 90 M41226-1 1 10 27-2 6903 2150 Battery spring B M41330-1 1 10 27-3 6919 3190 Key damper 61 M411615-1 6917 9300 Rubber foot M41109-3 5 20 6920 2290 Clip...
  • Page 30 MA0300941A...

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