Casio TV-350C Service manual

(with price)

POCKET TELEVISION

TV-350C

OCTOBER 1994

	Page
Specifications.............................................................................................	2
Block Diagram ...........................................................................................	3
Adjustment
Linear PCB.........................................................................................	4
Printed Circuit Boards ................................................................................	8
Wiring Diagram ........................................................................................	10
Electrical Parts List ..................................................................................	11
Mechanical Parts List...............................................................................	17
Exploded Views / Disassembly ................................................................	18
Schematic Diagrams and Waveforms .....................................................	19

INDEX

R

SPECIFICATIONS

Item			Specification
Reception Channels	VHF: Ch 2 ~ 12 ch			UHF: Ch 21 ~ 69
Power Voltage	DC 6.0 V
Power Consumption	Approx. 3.0 W
Current Consumption	Approx. 500 mA
Battery Life (with alkaline batteries)	Approx. 3.0 hours
	Batteries	: 4 AA size batteries
Power Supply	Car adaptor : CA-K65
	AC adaptor	: AD-K65
Connection Terminals	Earphone jack			: 3.5ø mini
	External power jack			: 6.0 V DC IN
Screen Size	1.6 inches
No. of Picture Element	39,600 (110 × 360) dots
Dimensions	122 mm (H) × 66 mm (ø)
Weight	210 g excluding batteries
	7.4 oz excluding batteries
Options	AC adaptor :		AD-K65
	Car adaptor :		CA-K65

— 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	IC500	5	IC300
Tuning
Voltage			Chroma	Common	LCD
Generator			Circuit	Driver
		6	IC700
			OSC
			Display		Segment
			Control
			A-D Converter		Driver
			Auto-Tuning
			Control
		8	Q800 ~ Q806
	VCC2 (3.95V±0.02V)	VR800	Display
Power
	VCC6 (30.5 ~ 39.0V)		Voltage
Supply	VCC7 (53.5 ~ 72.5V)	Brightness	Generator
	VEE1 (-6.3 ~ -7.9V)
		Control

1— Color Tuner: TU200 TEPE5-01

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 the tuner TU by 10 times (20dB).

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 M52045FP

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

6— OSC/A-D Converter/Display control/ Auto-Tuning Control : IC700 MSM662502 GSK-640F

Converts the color signal into a digital signal.

Also, generates the clock pulse for the display and controls the display.

7— Tuning Voltage Generator: IC500 MSC1169MS-K

Generates the tuning voltage with the tuning pulse (TU) output from 6.

8— Display Voltage Generator: Q800 ~ Q806 2SB1218A-R, 2SD1824R, S × 2, 2SD1819A-R × 5, 2SD1824-5

Generates the display voltages V0 ~ V4 with VEE1 and VCC7 outputs from the power supply.

— 3 —

		ADJUSTMENT
Linear PCB
1) Items to Be Adjusted
	Item	Measuring Instrument
	VCC2 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
	AGC adjustment	TV signal generator, Pattern generator, IF levelmeter
	Clock adjustment	Voltmeter

2) Adjustment and Test Point Locations

TOP VIEW

T201 T200

VR100

— 4 —

BOTTOM VIEW

TP7

VR200

TP2

Pad IF

TP3

TP4

VR700

TP6

TP5

VR301 VR300

3) Equipment Connection / Procedure

	VCC2 Voltage Setting
TV-350	Voltmeter
Set
	Output
	TP1

Input

Input

Input

Adjust

Output

Output

Result

Connection

Point

Signal

Connection

Point

VR100

Voltmeter

TP1

Adjust for 3.95 ± 0.02V

reading on voltmeter.

— 5 —

Video Detection Coil Adjsutment

* Open soldering pad IF.
Pattern	Signal	TV-350
generator	generator	Set	Oscilloscope
			Low-pass
	Input		filter
			Output
	TP2		TP3

R=180 ohm

C=0.01 μF

	Input	Input	Input	Adjust	Output	Output	Result
	Connection	Point	Signal		Connection	Point
	Pattern		Color bar
	generator				Low-pass filter		Adjust for DC level at mini-
		TP2	38.9MHz	T200		TP3
	Signal				Oscilloscope
			41 ± 3dBμ
	generator

AFT Coil Adjustment

* Open soldering pad IF.

Sweep	TV-350	Oscilloscope	Voltmeter
generator	Set
Input		Output
TP2		TP4

38.9 ± 5MHz

Adjust for 1.8 ± 0.2V reading on

Sweep

voltmeter.

TP2

(Sweep) Marker:

T201

Voltmeter

TP4

Confirm that the marker is at

generator

Oscilloscope

38.9MHz

the middle of S-curve on oscil-

70dBμ

loscope.

Contrast Adjustment

* Open soldering pad IF.

Pattern

Signal

TV-350

generator

generator

Set

Oscilloscope

Low-pass

filter

Input

Output

TP2

TP5

R=100 ohm

C=2700 pF

Pattern

Color bar

generator

Adjust step form wave to read

TP2

38.9MHz

VR300

Oscilloscope

TP5

Signal

0.75 ± 0.05 Vp-p.

70dBμ

generator

— 6 —

AGC Adjustment

	Pattern		Signal		TV-350
	generator		generator		Set		IF levelmeter
				Input		Output
				TP7		TP2
	Input	Input	Input	Adjust	Output	Output	Result
	Connection	Point	Signal		Connection	Point
	Pattern						Adjust for 81 ± 1 dBμ reading
	generator	TP7	Color bar	VR200	IF levelmeter	TP2
							on the IF levelmeter
	TV Signal		65 ± 5 dBμ
	generator
				Tint Adjustment
	* Open soldering pad IF.
	Pattern		Signal		TV-350
	generator		generator		Set		Oscilloscope
						Low-pass
						filter
				Input	Output
				TP2		TP3
							R=100 ohm
							C=2700 pF
							Adjust VR301 so that the dif-
	Pattern						ference between pulse A and
			Color bar				B is less that 0.1V.
	generator				Low-pass filter
		TP2	38.9MHz	VR301		TP3 Pulse A		Pulse B
	Signal				Oscilloscope
			70 dBμ
	generator

	Clock Adjustment
TV-350	Voltmeter
Set
	Output
	TP6

Adjust for 1.00 ± 0.05V

VR700 Voltmeter	TP6
	reading on voltmeter.

— 7 —