Casio EV-500B Service manual

(with price)

EV-500B(KX-615)

FEB. 1995

INDEX

R

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	VHF: 2 ~ 13 ch UHF: 21 ~ 69 ch
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
		Batteries	: 3 AA size batteries
6.	Power supply	Car adaptor : CA-K65
		AC adaptor	: AD-K65
		Earphone jack		: 3.5ø mini
7.	Connection terminals	External power jack		: 6.0 V DC IN
		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 —

BLOCK DIAGRAM

Antenna

			3	IC200	4	IC600	Speaker
1	TU200	2	Q200	Video
					VR600
				Sound Det.		Audio
	Tuner		IF Amp.	FM		Amp.
				AFT Circuit	Volume
				AGC Circuit	Control

	7	IC270	IC300
		5
	Tuning
	Voltage		Chroma	LCD
	Generator
			Circuit

6 IC700

Display

Control

Auto-Tuning

Control

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

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 —

CIRCUIT DESCRIPTION

POWER SUPPLY

Vcc1-1

L102

Vcc2-2

330u

(3.9 V)

CP100

2

T100

3

D158 MA143A

R160

Vcc7 (29.5 V)

LC12U-35

R108

270K

R110

270

C146

68

CP110

Vcc6 (11 V)

4

220p

Q110

2SD1819A-R

D156 MA142WK

CP111

Q111

1

5

L101

Vcc2-1 (4.5 V)

2SD1119-R

D100

R107

C137

D154 MA142WK

100u

CP113

MA142WK

33K

B6800p

6

6.3 V 220

D110

MA3051-L

Q101

C140

R115

9

D152

2SD1819A-R

CH470p

100

7

MA142WK

VEE1 (-7.5 V)

B1500p

C100

BH102K

2.2K

C145

D150

CP114

VEE2 (-18 V)

6

8

MA142WK

C105 2.2

C114 6.3 V 220

C116 6.3 V 220

C110 25 V 10

C112 16 V 47

C118 16 V 22

C120 35 V 22

TM100

R105 3.3K

R113

C150 OPEN

R150 33K

CP115

VR100

2K

CP101

GND

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 —

TP2 (ANT)

IF Pad	TP2
VR200
TP3 (VIDEO)
TP4 (AFT)

TP1(VCC2·1)

TP8 (VCOM)

VR740

TP6(HD)

VR301

VR303

TP5(VC)

VR300

Bottom View

Equipment Connection / Adjustment Procedure

VCC2-1 Voltage Setting

EV-500

16-169

Voltmeter

set

Output

TP1

Input

Input

Input

Adjust

Output

Output

Result

Connection

Point

Signal

Connection

Point

VR100

Voltmeter

TP1

Adjust to obtain a 4.50 ± 0.02 V

reading on the voltmeter.

— 6 —

	Video Detection Coil Adjustment
* Desolder the IF pad to open.
Pattern	Signal	EV-500
generator	generator	set	Oscilloscope
		Low-pass
		filter
	Input	Output
	TP2	TP3

	Input	Input	Input	Adjust	Output	Output	Result
	Connection	Point	Signal		Connection	Point
	Pattern		Color bar
	generator	TP2		T200	Low-pass filter	TP3	Adjust to obtain the minimum
	Signal		45.75 MHz		Oscilloscope		DC level.
			45 ± 3 dBμ
	generator

AFT Coil Adjustment

* Desolder the IF pad to open.

		Sweep	EV-500
		generator	set		Oscilloscope		Voltmeter
			Input		Output
			TP2		TP4
			45.75 ± 5 MHz				Adjust to obtain a 1.4 ± 0.2 V
	Sweep						reading on the voltmeter.
		TP2	(sweep) marker:	T201	Voltmeter	TP4
							Confirm that the marker is at
			45.75 MHz		Oscilloscope
	generator						the middle of the S-curve on
			70 ± 3 dBμ
							the oscilloscope.
				Contrast Adjustment
	* Desolder the IF pad to open.						Vcc2-3
	Pattern		Signal		EV-500	10 kohm
	generator		generator		set		Oscilloscope
						CP312 (KILLER)
					Input	Output
					TP2	TP5

	Pattern						Adjust so
			Color bar				that the step
	generator
		TP2	45.75 MHz	VR300	Oscilloscope	TP5	form wave
	Signal
			70 ± 3 dBμ				becomes 2.2
	generator						± 0.1 Vp-p.

2.2± 0.1 V P.P

— 7 —

BCC Adjustment

* Desolder the IF pad to open.

	Pattern		Signal		EV-500
	generator		generator		set		Oscilloscope
				Input		Output
				TP2		CP339(VC)
	Input	Input	Input	Adjust	Output	Output	Result
	Connection	Point	Signal		Connection	Point
	Pattern						Adjust VR301 so that the
							difference	Pulse A Pulse B
	generator		Color bar
							between pulses
	Signal	TP2	45.75 MHz	VR301	Oscilloscope	TP5
							A and B is less
			70 ± 3 dBμ
	generator
							than 0.2 V.
				AGC Adjustment
	* Short the IF	pad.
	Pattern		Signal		EV-500
	generator		generator		set		IF levelmeter
				Input		Output
				TP7		TP2

Pattern
generator	TP7	Color bar		VR200	IF levelmeter	TP2	Adjust to obtain a 84 ± 2 dBμ
TV signal		65 ± 5 dBμ					reading on the IF levelmeter.
generator
				Vcom Adjustment
		EV-500
			set		Oscilloscope

Output

TP8

Adjust VR303 so that the

high level of the square wave

VR303

Oscilloscope

TP8

is at -0.5

-0.5 ± 0.25 V

± 0.25 V.

5.0 ± 0.5 V

— 8 —