Casio TV-1800B Service manual

R

TV-1800B (NTSC)

(KX-523)

(without price)

FEB. 1997

<

TUNING

>

CONTENTS

Page

SPECIFICATIONS.....................................................................................1

BLOCK DIAGRAM.................................................................................... 2

CIRCUIT OPERATIONS ...........................................................................3

PRINTED CIRCUIT BOARDS...................................................................4

PARTS LIST.............................................................................................. 6

EXPLODED VIEW.....................................................................................9

SCHEMATIC DIAGRAMS....................................................................... 11

WAVEFORMS ......................................................................................... 13

— 1 —

Item Specification

1. Power voltage DC 6.0 V

2. Power consumption Approx. 3.6 W

3. Current consumption Approx. 600 mA

4. Battery life (with alkaline batteries) Approx. 2.5 hours

Batteries : 4 × LR6 (D) size batteries

5. Power supply Car adaptor : CA-K65

AC adaptor : AD-K65

Earphone jack : 3.5 ø mini

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

External antenna jack : 3.5 ø mini

7. Screen size 2.5 inches

8. No. of picture element 118,800 (540 × 220) dots

9. Dimensions 135 mm (H) × 91 mm (W) × 38 mm (D)

10. Weight 240 g without batteries

AC adaptor : AD-K65

11. Options Car adaptor : CA-K65

Antenna matching device : AS-35S

SPECIFICATIONS

Color System TV System Channel

NTSC M / M US VHF: 2 ~ 13 ch UHF: 14 ~ 69 ch

— 2 —

Antenna

1 TU200 2 Q200

3 IC200

7

Tuning

Voltage

Generator

VR600

Volume

Control

4 IC600 Speaker

IC300

IC700

Common

Driver

LCD

Segment

Driver

Chroma

Circuit

Osc.

Display

Control

A-D Converter

Auto-Tuning

Control

5

6

8 Q800 ~ Q806, Q810, Q811

VR800

Display

Voltage

Generator

Brightness

Control

VCC2 (4.3 ± 0.02 V)

VCC7 (41.6 ~ 51.6 V)

VEE1 (-6.5 ~ -8.0 V)

IC500

Power

Supply

Audio

Amp.

IF Amp.Tuner

Video

Sound Det.

FM

AFT Circuit

AGC Circuit

1 — Color Tuner: TU200 TEPE5-02

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 the tuner TU 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 M52045FP

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

6 — Osc./A-D Converter/Display Control/ Auto-Tuning Control : IC700 MSM6625-01 GSK-640E

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: IC800 BA10358F, Q800 ~ Q806 Q810 Q811 2SD1149-S,

2SD601A-R×3, 2SB709A-R

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

BLOCK DIAGRAM

— 3 —

Signal Name

Function

Signal Name

Function

D1 ~ D6 Display data output terminal MTB Mute control terminal

SNB Data latch signal TU Tuning control pulse output terminal

CDB Scanning start signal VLB VHF High/Low channel select signal

output terminal

CFB Output voltage changeover signal UHF VHF/UHF select signal

CNB Scanning signal shift lock signal AVB

KCB Key input terminal

KDB

SCB Brightness modulation pulse control AFT AFT voltage input terminal

STB Sampling start signal M1 ~ M10 Mode select signal input terminal

ECB Signal input terminal controlling the

TE1 ~ TE6

Test terminal

segment drive terminal to "H" during

no display

CK1, CK2 Clock pulse output terminal R, G, B Original color

OSC1 Oscillator frequency control terminal RLL "L" level voltage input terminal of

OSC2 video signal

PD Clock pulse adjustment terminal RHH "H" level voltage input terminal of

video signal

C-S Synchronizing pulse input terminal PS1 Mode control signal

HDB Horizontal synchronizing signal input VSS1 Power supply voltage input terminal

terminal

VDD1 VDD voltage input terminal

CIRCUIT OPERATIONS

IC700

AD2

AD1

R

G

B

RLL

VDD2

RHH

M7

M8

M9

M10

PSi

VSS1

A/D

Mode

Control

Test Control Mode Control

AFT

Control

VSS2 TE1

TE2

TE3

TE4

TE5

TE6

M6 M5 M4 M3 M2 M1 AFT

KDB

KCB

UHF

AVB

MTB

VLB

TU

VDD1

C-S

PD

OSC1

OSC2

Key

Switch

Control

Mute

Control

Synchronism

Judgment

Frequency

Separator

Phase

Comparator

Oscillator

Frequency

Divider

Horizontal

positioning

Control

Vertical

positioning

Control

Data Output

Channel

bar

Control

Tuning Voltage

UP/DOWN Counter

Pulse Width

Modulation D/A

Sweep

Control

Frequency

Divider

Tuning Control

Test

Circuit

Display

Control

D1 D2 D3 D4 D5 D6 CDB CFB CNB ECB

SNB

SCB STB HDB CK1 CK2