Casio CTK-750 manual Replacing the DSP HG51A115A01FD, Electrical

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Electrical

Current Drain with 12V DC:

390 mA ± 20%

No Sound Output

Maximum Volume

1700 mA ± 20%

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 load each cannel):

 

with key D4 pressed in FSynth-Bass-2 tone on L-ch

850 mV ± 20%

with key G4 pressed in FSynth-Bass-2 tone on R-ch

800 mV ± 20%

Phone Output Level (Vrms with 8 Ω load each channel):

280 mV ± 20%

with key D4 pressed in FSynth-Bass-2 tone on L-ch

with key G4 pressed in FSynth-Bass-2 tone on R-ch

260 mV ± 20%

Speaker Input Level:

5200 mV ± 20%

with key D4 pressed in FSynth-Bass-2 tone on L-ch

with key G4 pressed in FSynth-Bass-2 tone on R-ch

5600 mV ± 20%

Minimum Operating Voltage:

5.5 V

REPLACING THE DSP (HG51A115A01FD)

Note: To increase productivity ,the DSP HG51A115A01FD is sticked on the main PCB with a double-side adhesive tape, then its leads are soldered.

Remove the DSP according to the following procedures.

1.Prepare isopropyl alcohol and a flat IC desoldering machine (Spot Heater HS-600).

2.Apply plenty of the alcohol to the adhesive tape from the reverse side of the main PCB. (Fig. 1) There is a hole on the PCB just under the LSI, and the adhesive tape can be seen through the hole.

3.Leave it more than one minute so that the alcohol weaken adhesive power fully.

4.Using a proper size of nozzle, apply heat to leads of the LSI with the desoldering machine.

5.Grasp the LSI with tweezers, and using gentle force vibrate the tweezers to feel melting solder. (Fig.2)

6.Remove the LSI after meltingsolder at every leads wholly.

Spot Heater HS-600

Alcohl

HG51A115A

LSI

- S

Fig.1

Fig.2

— 2 —

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Contents CTK-750 Contents Specifications GeneralReplacing the DSP HG51A115A01FD ElectricalBlock Diagram UPD6376CXCircuit Description Key MatrixReset Circuit Nomenclature of KeysButton Matrix MidiCPU HD6433298A18P Pin No Terminal In/Out FunctionGate Array UPD65005C-578 Digital Signal Processor HG51A115A01FD Block diagram of DSP and DAC circuit Key Touch LSI HG52E35P Filter Block Power Amplifier LA4620 Power Supply CircuitName Voltage For operation AvddWiring Diagram M5712-CN1MMajor Waveforms Page PCB View and Major Check Points Schematic Diagrams Console PCB M5712-CN1M Keyboard PCBs M615T-KY1M, KY2M Exploded View IC Lead Identification and Internal Diagram S8053ANOM5218APR PC900VEB C E Q2 2SD1762E,F Q4 2SB1274Be C B Parts List N N FOB Japan Code No Parts Name Specification Yen Unit Price Lower Case Screws MA0300941A