Casio TV-1800B Service manual

TV-1800B (NTSC)

(KX-523)

FEB. 1997

(without price)

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

SPECIFICATIONS

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

Color System TV System Channel

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

— 1 —

Antenna

BLOCK DIAGRAM

Power Supply

1 TU200 2 Q200

IF Amp.Tuner

IC500

Tuning Voltage Generator

VCC2 (4.3 ± 0.02 V) VCC7 (41.6 ~ 51.6 V) VEE1 (-6.5 ~ -8.0 V)

VR800

Brightness Control

3 IC200

Video Sound Det. FM AFT Circuit AGC Circuit

IC300

Chroma Circuit

IC700

Osc. Display Control A-D Converter Auto-Tuning Control

8 Q800 ~ Q806, Q810, Q811

Display Voltage Generator

VR600

Volume Control

4 IC600 Speaker

Audio Amp.

Common Driver

LCD

Segment Driver

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.

— 2 —

CIRCUIT OPERATIONS

AD2 AD1

RLL

VDD2

RHH

M7 M8 M9

M10

PSi

VSS1

IC700

B G R

VSS2 TE1

A/D

Mode

Control

Data Output

TE2

TE4

TE5

TE6

M6 M5 M4 M3 M2 M1 AFT

Frequency

Divider

Channel bar Control

Vertical

positioning

Control

TE3

Test Control Mode Control

Test

Circuit

Display Control

Sweep

Control

Tuning Control

Tuning Voltage UP/DOWN Counter

Pulse Width Modulation D/A

Horizontal

positioning

Control

AFT

Control

Phase

Comparator

Frequency

Divider

Key

Switch

Control

Mute

Control

Synchronism

Judgment

Frequency

Separator

Oscillator

KDB KCB AVB UHF

MTB

VLB

VDD1 C-S PD

OSC1 OSC2

D1 D2 D3 D4 D5 D6 CDB CFB CNB ECB

Signal Name

Function

SCB STB HDB CK1 CK2

SNB

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

— 3 —

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