Casio LA4620 Amplifier Circuit Diagram for WK-1500 Keyboard

Page 12

POWER AMPLIFIER (IC201: LA4620)

 

 

 

 

 

 

The power amplifier is a two-channel amplifier with standby switch.

 

 

 

 

+

 

 

 

 

 

 

19 Boot11

IN11+

3

 

 

 

 

 

 

 

Input

 

Pre-drive

 

 

Power

 

20 OUT11

 

 

 

 

 

 

IN11–

5

Amp.

 

Amp.

 

 

Amp.

 

 

 

 

 

 

 

 

 

 

 

 

 

RL Short

 

 

 

 

 

 

 

 

 

 

 

 

21 PoGND1

 

 

 

 

 

Protector

 

 

 

 

4

 

 

 

 

 

 

IN12–

 

 

 

 

 

 

 

Input

 

Pre-drive

 

 

Power

 

22 OUT12

 

 

 

 

 

 

 

 

Amp.

 

Amp.

 

 

Amp.

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

23 Boot12

 

 

 

Terminal

 

Ripple

Pop Noise

 

 

 

 

Protection

 

Prevention

1 VCC1

PriGND

6

 

 

Filter

 

 

Circuit

 

 

 

Circuit

 

 

 

+

 

 

 

 

 

 

18 Boot21

IN21+

9

 

 

 

 

 

 

 

Input

 

Pre-drive

 

 

Power

 

17 OUT21

 

 

 

 

 

 

IN21–

7

Amp.

 

Amp.

 

 

Amp.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RL Short

 

 

 

 

 

 

 

 

 

 

 

 

15 PoGND2

 

 

 

 

 

Protector

 

 

 

 

 

 

 

 

 

 

 

IN22–

8

 

 

 

 

 

 

 

Input

 

Pre-drive

 

 

Power

 

14 OUT22

 

 

 

 

 

 

 

 

Amp.

 

Amp.

 

 

Amp.

 

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12 Boot22

 

 

16

2

10

 

 

11

13

 

 

 

NC

DC

MUTE

 

 

VCC2

ADJ

 

LED DRIVING

 

 

LVDD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

La ~ Lg, Lp

 

 

LD0 ~ LD7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CPU

 

 

 

 

 

 

 

Q15 ~ Q18

 

 

 

 

 

 

 

 

 

 

 

LSI14

 

IC301

 

LED Driver

 

 

 

 

 

 

 

 

 

 

 

 

 

BA612

 

IC17

 

 

 

 

HD6433294A19F

LED Driver

 

 

 

 

 

 

UPD65611GB-019-3BA

 

 

 

 

 

 

 

 

 

 

P40

 

 

 

 

 

 

KO0 ~ KO3, KO5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P41

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LG

RESET CIRCUIT

KO Signal Generator

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 the working storage RAM.

When the power switch is pressed, the CPU receives a low pulse of POWER signal. The CPU provides APO signal to the power supply circuit and raises RESET signal to +5 V to reset the DSP, the key controller and the KO signal generator.

Battery set

VDD

 

VDD

 

RESET

 

Reset IC

CPU

IC13

LSI14

RH5VL36AA

HD6433294A19F

POWER

-NMI

From power switch

 

APO

P42

 

To power supply circuit

 

 

DVDD

 

DVDD

 

 

 

 

 

 

 

KO Signal Generator

 

DSP

LSI17

 

LSI11

UPD65611GB-019-3BA

 

HG51B155FD-1

 

 

 

 

 

-RESET

 

VDD

 

DVDD

 

 

 

 

 

 

 

 

Working Storage RAM

 

Key Controller

LSI15

 

LSI16

TC55257DFL-70L

 

HG52E35P

 

 

 

 

 

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Image 12
Contents WK-1500 Contents SpecificationsElectrical MidiIN, OUT Block Diagram Reset RH5VL36AACircuit Description KEY MatrixPower Supply Circuit Nomenclature of KeysButton Matrix Digital Signal Processor LSI11 HG51B155FD-1 CE1, Trsb GND7VCC6 CK0Eoeb VCC7Eceb VCC4KEY Controller LSI16 HG52E35P Filter Block Power Amplifier IC201 LA4620 Reset CircuitLED Driving CPUMajor Waveforms CH1 CH2CH2 CH3 CH1 CH2 C CH3Printed Circuit Boards Main PCB JCM717-MA1MSchematic Diagrams Main PCB JCM717-MA1MSUB PCB KDM717-MA2M Console PCBs KDM717-CN1M/CN2/CN3/CN4 Keyboard PCBs JCM762T-KY1M/KY2M/KY3 Exploded View Parts List Keyboard PCBs Code No Parts Name Specification MA0900761A Sep

WK-1500 specifications

The Casio WK-1500 is a versatile and user-friendly keyboard designed for aspiring musicians and experienced players alike. Part of Casio’s renowned line of portable keyboards, the WK-1500 combines advanced features with a compact design, making it a suitable choice for both home practice and live performances.

At the heart of the WK-1500 is its impressive sound engine, which boasts an extensive library of sounds. With over 600 built-in tones, including a variety of acoustic and electronic instruments, players can easily find the perfect voice for any musical genre. The keyboard also features over 180 rhythms, allowing users to explore a broader musical landscape and enhance their compositions with supportive accompaniments.

One of the standout features of the WK-1500 is its 76 full-size touch-sensitive keys. This is particularly beneficial for pianists, as the touch sensitivity provides a more responsive playing experience. Players can express dynamics and nuances in their performances, enriching their musical interpretations.

The WK-1500 is also equipped with a powerful performance tool known as the "Advanced Synthesizer." This technology allows users to create and modify sounds in real-time, providing endless creative possibilities. Additionally, the keyboard includes a built-in arpeggiator that offers various patterns and styles, further expanding the creative potential.

For those who enjoy composing and recording, the WK-1500 offers built-in song storage with the ability to save and play back original compositions. Users can also connect the keyboard to a computer via USB, making it easy to transfer MIDI data or use the keyboard in conjunction with digital audio workstations.

Another notable characteristic of the WK-1500 is its durability and portability. Weighing in at just under 10 pounds, it is lightweight enough to transport easily. The keyboard also comes with a robust stand and a power adapter, ensuring that musicians can play wherever they go.

In conclusion, the Casio WK-1500 is a feature-packed keyboard that caters to the needs of a wide range of musicians. With its extensive sound library, touch-sensitive keys, advanced synthesizer capabilities, and portability, the WK-1500 stands out as an excellent choice for both learning and performing, ensuring it remains a popular option in the world of portable keyboards. This combination of features, technology, and user-friendly design makes it a valuable instrument for music enthusiasts of all levels.