Casio EV-500B Service manual

EV-500B(KX-615)

INDEX

FEB. 1995

(with price)

CONTENTS

SPECIFICATIONS ......................................................................................... 2

BLOCK DIAGRAM ........................................................................................ 3

CIRCUIT DESCRIPTION ............................................................................... 4

ADJUSTMENT............................................................................................... 5

TROUBLESHOOTING................................................................................. 10

PRINTED CIRCUIT BOARDS ..................................................................... 11

WIRING DIAGRAM...................................................................................... 13

EXPLODED VIEW ....................................................................................... 14

ELECTRICAL PARTS LIST......................................................................... 15

MECHANICAL PARTS LIST ....................................................................... 21

IC AND TRANSISTOR LEAD IDENTIFICATION ........................................ 22

SCHEMATIC DIAGRAMS ........................................................................... 24

WAVEFORMS.............................................................................................. 26

— 1 —

SPECIFICATIONS

Item Specification

1. Reception channels

2. Power voltage DC 6.0 V

3. Power consumption Approx. 3.7 W

4. Current consumption Approx. 617 mA

5. Battery life (with alkaline batteries) Approx. 2.0 hours

6. Power supply Car adaptor : CA-K65

7. Connection terminals External power jack : 6.0 V DC IN

VHF: 2 ~ 13 ch UHF: 21 ~ 69 ch

Batteries : 3 AA size batteries AC adaptor : AD-K65

Earphone jack : 3.5ø mini External antennea jack : 3.5ø mini

Audio / Video jack : 3.5ø

8. Screen size 2.5 inches

9. No. of Picture element 61,380 (220 × 279) dots

10. Dimensions 75 (W) × 26.7 (D) × 120.8 (H) mm 3 (W) × 1 (D) × 4 3/4 (H)

11. Weight 191 g excepting batteries

6.7 oz excepting batteries

12. Standard accessories Test batteries (R6 × 3)

AC adaptor : AD-K65,64

13. Options Car adaptor : CA-K65 RF connector : CF-13 Antenna matching device : AS-35S

14. Body color Black

— 2 —

Antenna

BLOCK DIAGRAM

Power Supply

1 TU200 2 Q200

IF Amp.Tuner

IC270

Tuning Voltage Generator

VCC2 (4.5 ± 0.02 V) VCC7 (25.9 ~ 31.3 V) VCC6 (10.8 ~ 12.0 V) VEE1 (–8.5 ~ –7.5 V) VEE2 (–19.8 ~ –17.2 V)

3 IC200

Video Sound Det. FM AFT Circuit AGC Circuit

Det

IC300

Chroma Circuit

IC700

Display Control Auto-Tuning Control

4 IC600 Speaker

VR600

Audio

Amp. Volume Control

LCD

1 — Color tuner: TU200 TEPU5-02

Selects a desired radio wave and changes it to the video IF signal.

2 — Video IF amp.: Q200 2SC4238

Amplifies the video IF signal output from tuner TU200 by 10 times (20 dB).

3 — Video det./Sound det./FM det./AFT/AGC: IC200 M51348FP

Eliminates the carrier wave in the video IF signal, and picks up the video signal and the sound IF signal. Also, the sound signal is picked up from the sound IF signal by FM detection.

4 — Audio amp.: IC600 NJM2070M

Sound amplification.

5 — Chroma circuit: IC300 IR3P90Y

Generates the tricolor (red, green, and blue) from the video signal.

6 — Display control/Auto-tuning control: IC700 MSM6770GS

Controls the display.

7 — Tuning voltage generator: IC270 BA10358F

Generates the tuning voltage with the tuning pulse output from 6.

— 3 —

POWER SUPPLY

CIRCUIT DESCRIPTION

Vcc1-1

6.3 V 220C100

GND

CP100

D100

R107

MA142WK 33K B6800p

D110

2.2

C105

Q101

2SD1819A-R

MA3051-L

BH102K

TM100

VR100

R105

R110

270K

R108

Q110 2SD1819A-R

C137

CH470p

3.3K

2SD1119-R

C140

2.2KR113

270

Q111

R115

100

C145

B1500p

T100

LC12U-35

CP101

D158 MA143A

C146

D156 MA142WK

D154 MA142WK

D152

MA142WK

D150

MA142WK

220p

C110 25 V 10

R160

C150 OPEN

L101 100u

C114 6.3 V 220

C112 16 V 47

L102 330u

C116 6.3 V 220

C118 16 V 22

Vcc7 (29.5 V)

CP110

CP111

Vcc2-1 (4.5 V)

CP113

VEE1 (-7.5 V)

CP114 VEE2 (-18 V)

CP115

C120 35 V 22

R150 33K

Vcc2-2

(3.9 V)

Vcc6 (11 V)

GND

Figure 1

The power supply consists of a DC-DC converter and the associated circuit and supplies the voltages as shown in Table 1.

Name Voltage Function

VCC2-1 4.50 ± 0.02 V Main voltage

VCC7 25.9 ~ 31.3 V Tuning voltage VCC6 10.8 ~ 12.0 V Display voltage VEE1 –8.5 ~ –7.5 V Display voltage VEE2 –19.8 ~ –17.2 V Display voltage

Table 1

— 4 —

ADJUSTMENT

LINEAR PCB Items to Be Adjusted

Item Measuring Instrument

VCC2-1 voltage setting Voltmeter Video detection coil adjustment TV signal generator, pattern generator, oscilloscope,

low-pass filter AFT coil adjustment Sweep generator, oscilloscope, voltmeter Contrast adjustment TV signal generator, pattern generator, oscilloscope

Tint adjustment TV signal generator, pattern generator, oscilloscope AGC adjustment TV signal generator, pattern generator, IF levelmeter Vcom adjustment Photo diode, photo sensor amp., bandpass filter, oscilloscope Free-Running frequency adjustment

Frequency counter

Adjustment and Test Point Locations

VR100

T201T200

Top View

— 5 —

TP3 (VIDEO)

TP4 (AFT)

TP8 (VCOM)

VR200

TP2IF Pad

VR740

TP2 (ANT)

TP1(VCC2·1)

TP6(HD)

VR303

TP5(VC)

VR300

Bottom View

Equipment Connection / Adjustment Procedure

VCC2-1 Voltage Setting

EV-500

16-169

set

Output

TP1

VR301

Voltmeter

Input Input Input Output Output

Connection Point Signal Connection Point

Adjust Result

VR100

Voltmeter

TP1

— 6 —

Adjust to obtain a 4.50 ± 0.02 V reading on the voltmeter.

* Desolder the IF pad to open.

Pattern generator

Signal generator

Video Detection Coil Adjustment

EV-500

set

Low-pass filter

Input TP2

Output

TP3

Oscilloscope

Input Input Input Output Output

Connection Point Signal Connection Point

Adjust Result

Pattern generator

Signal generator

TP2 T200 TP3

Color bar

45.75 MHz 45 ± 3 dBµ

Low-pass filter Oscilloscope

AFT Coil Adjustment

* Desolder the IF pad to open.

Sweep generator

Input TP2

EV-500

set

Oscilloscope

Output

TP4

45.75 ± 5 MHz

Sweep generator

(sweep) marker:

TP2 T201 TP4

45.75 MHz

Voltmeter Oscilloscope

70 ± 3 dBµ

Adjust to obtain the minimum DC level.

Voltmeter

Adjust to obtain a 1.4 ± 0.2 V reading on the voltmeter. Confirm that the marker is at the middle of the S-curve on the oscilloscope.

* Desolder the IF pad to open.

Pattern generator

Signal

TP2 VR300 TP5

Color bar

45.75 MHz 70 ± 3 dBµ

generator

Signal generator

Contrast Adjustment

EV-500

set

Input TP2

Oscilloscope

— 7 —

Vcc2-3

10 kohm

CP312 (KILLER)

Output TP5

Adjust so that the step form wave becomes 2.2 ± 0.1 Vp-p.

Oscilloscope

2.2 ± 0.1 V P.P

* Desolder the IF pad to open.

BCC Adjustment

Pattern generator

Signal generator

EV-500

set

Input TP2

Input Input Input Output Output

Connection Point Signal Connection Point

Adjust Result

CP339(VC)

Pattern generator

Signal generator

TP2 VR301 Oscilloscope TP5

Color bar

45.75 MHz 70 ± 3 dBµ

AGC Adjustment

* Short the IF pad.

Pattern generator

Signal generator

EV-500

set

Oscilloscope

Output

Adjust VR301 so that the difference between pulses A and B is less than 0.2 V.

IF levelmeter

Pulse BPulse A

Pattern generator

TV signal generator

Input TP7

Color bar

TP7 VR200 IF levelmeter TP2

65 ± 5 dBµ

Vcom Adjustment

EV-500

set

Oscilloscope

Output TP8

VR303 Oscilloscope TP8

Output TP2

Adjust to obtain a 84 ± 2 dBµ reading on the IF levelmeter.

Adjust VR303 so that the high level of the square wave is at -0.5 ± 0.25 V.

5.0 ± 0.5 V

-0.5 ± 0.25 V

— 8 —

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