(without price)

TV-1800B (NTSC)

(KX-523)

FEB. 1997

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 1. Power voltage 2. Power consumption 3. Current consumption 4. Battery life (with alkaline batteries) DC 6.0 V Approx. 3.6 W Approx. 600 mA Approx. 2.5 hours Batteries 5. Power supply : 4 LR6 (D) size batteries Specification
Car adaptor : CA-K65 AC adaptor : AD-K65 Earphone jack : 3.5 mini : 6.0 V DC IN : 3.5 mini

6. Connection terminals

External power jack External antenna jack
7. Screen size 8. No. of picture element 9. Dimensions 10. Weight
2.5 inches 118,800 (540 220) dots 135 mm (H) 91 mm (W) 38 mm (D) 240 g without batteries AC adaptor : AD-K65 : CA-K65

11. Options

Car adaptor
Antenna matching device : AS-35S

Color System NTSC

TV System M/M US
Channel VHF: 2 ~ 13 ch UHF: 14 ~ 69 ch

BLOCK DIAGRAM

Antenna
TU200 Tuner 2 Q200 IF Amp.
ICVideo Sound Det. FM AFT Circuit AGC Circuit VR600 Audio Amp. Volume Control IC600 Speaker
IC300 Chroma Circuit Common Driver LCD

Tuning Voltage Generator

IC700 Osc. Display Control A-D Converter Auto-Tuning Control

Segment Driver

Q800 ~ Q806, Q810, Q811 Display Voltage Generator

Power Supply

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

Brightness Control

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-R3, 2SB709A-R Generates the display voltages V0 ~ V4 with VEE1 and VCC7 outputs from the power supply.

CIRCUIT OPERATIONS

TE2 VSS2 TE1 TE3 TE4 TE5 TE6 M6 M5 M4 M3 M2 M1 AFT Key Switch Control KDB KCB AVB UHF
AD2 Test Control AD1 B G A/D R Tuning Control RLL VDD2 RHH Pulse Width Modulation D/A M7 M8 M9 M10 PSi VSS1 Data Output Display Control Vertical positioning Control Horizontal positioning Control Mode Control Channel bar Control Tuning Voltage UP/DOWN Counter Test Circuit Frequency Divider Sweep Control Mode Control

AFT Control

Mute Control
VLB Synchronism Judgment TU Frequency Separator Phase Comparator VDD1 C-S PD

Frequency Divider

OSC1 Oscillator OSC2

D1 D2 D3 D4 D5 D6

CDB CFB CNB ECB

SNB SCB STB HDB

CK1 CK2
Signal Name D1 ~ D6 SNB CDB CFB CNB
Function Display data output terminal Data latch signal Scanning start signal Output voltage changeover signal Scanning signal shift lock signal
Signal Name MTB TU VLB UHF AVB KCB KDB AFT M1 ~ M10 TE1 ~ TE6
Function Mute control terminal Tuning control pulse output terminal VHF High/Low channel select signal output terminal VHF/UHF select signal Key input terminal AFT voltage input terminal Mode select signal input terminal Test terminal

SCB STB ECB

CK1, CK2 OSC1 OSC2 PD C-S HDB VDD1

Brightness modulation pulse control Sampling start signal Signal input terminal controlling the segment drive terminal to "H" during no display Clock pulse output terminal Oscillator frequency control terminal Clock pulse adjustment terminal Synchronizing pulse input terminal Horizontal synchronizing signal input terminal VDD voltage input terminal

R, G, B RLL RHH PS1 VSS1

Original color "L" level voltage input terminal of video signal "H" level voltage input terminal of video signal Mode control signal Power supply voltage input terminal

PRINTED CIRCUIT BOARDS

TOP VIEWS

C202 C603

C233 C236 R209 R207 F200 C210 R210

Linear

C208 C606

C207 L102 C110

R825 R824

C113 L101

C810 C845 D803

R700 D703

R725 R727

C831 C832

R726 C751 C741 R703 C750 C761 C755 R719 R738 D705 C756 R733

C309 R342

Back Light

C951 C950

R950 L950

BOTTOM VIEWS Linear

R645 Q200
R205 C234 R203 C630 R201 IC600 R202 R641 C235 C240 C265 CP204 CP221 R502 C642 R606 HP200 R501 R500 C243 VR200 R611 R215 C259 R208 D100 R224 R615 R610 VR100 C245 C246 R607 R236 C249 R101 IC500 C550 R229 R212 R223 C830 IC200 Q100 CP245

C237 R541

L200 R204
IC800 R836 R835 R834 R820 R821 R822 Q810 Q811

Q804 C257 Q805 R230

R241 D500 C264 CP240
Q101 C545 R102 R111 Q111 R103 R117 C140 C145
Q806 R833 D805 R817 C840 C835 R815 R816 C765
C261 C262 C263 R246 R827 Q802 R809 R810 C290 Q800 D700 L700 C291 VR300
D150 R115 D152 D155 Q300 R306 R305 + C301 R307

Q801 Q803

C740 C742

C335 R310 C340

CP700 R730 R311 C345 R322 R312 C346 C776 VR700 R740 C347
R336 R335 R326 R331 R330 C350 C185

R325 VR301 C351 R343

PARTS LIST

LINEAR PCB

Q Quantity used per unit R Rank 8

EXPLODED VIEW

12-2 12-3

SCHEMATIC DIAGRAMS

LINEAR
Antenna External Antenna Jack Earphone Jack
Speaker 1 Audio Amplifier Circuit 13

IF pad DC in Batteries

IF detection Circuit

To Back Light

Display Voltage Generator Circuit

Power Switch

Tuning Voltage Generator Circuit 4

7 Power Supply Circuit

Chroma Circuit
Display Controller Circuit

To LCD

BACK LIGHT

WAVEFORMS

112 mV 0.8 V

600 mV

63.5 s

1 Q200 Collector

2 IC200 Pin 19

3 IC200 Pin 18

0.24 s

4 IC300 Pin 23

5 IC300 Pins 10, 11, 12

6 IC300 Pin 5

10 V 600 mV

7 IC300 Pin 4

8 IC300 Pin 1

9 Q111 Collector

100 ns

360 ns

0 Q111 Base

A IC700 Pin 17

B IC700 Pin 14

C Q806 Base

D IC700 Pin 12
8-11-10, Nishi-Shinjuku Shinjuku-ku, Tokyo 160, Japan Telephone: 03-3347-4926

MA0300271A

Basic Information for Casio Pocket Television

Vol.3 CIRCUIT OPERATION

Contents PAGE TELEVISION TRANSMISSION SYSTEM... 1 Color System.... 1 TV System.... 1 Channel System... 1 Details of Color System... 2 Details of TV System... 2 Details of TV Channel... 3 World TV Broadcast System... 5 Casio TV Model... 6 BLOCK DIAGRAM.... 7 VHF, UHF.... 7 Rod Antenna.... 7 PCB Ass'y.... 8 Display Ass'y.... 8 AD PCB... 9 Back Light.... 9 Power Supply.... 9 CIRCUIT OPERATION.... 11 Tuner....11 IC200.... 12 IC300....13 IC400....16 IC700....17 Tuning Operation....18 Adjustment... 19 Troubleshooting.... 20 Trouble example.... 28 SCHEMATIC DIAGRAM & WAVEFORMS.. 29 Waveforms.... 32
TELEVISION TRANSMISSION S Y S T E M
T h r e e Systems TV transmission systems are not the same throughout the world: Color system, TV system and Channel are different. The countries for which a particular model is suitable are indicated in the sales literature and instruction booklet supplied, and are printed on the box in which each television is packed. Color system There are three color transmission systems in the world: NTSC, PAL and SECAM. If the color systems are different, TV does not get in color. e.g. Color System PAL NTSC Color System SECAM PAL TV System M/M M/M TV System B/G,H B/G,H Channel System US US Channel System CCIR CCIR

Brazil U.S.A.

Saudi Arabia Germany
T V System There are fourteen TV systems in the world: From A to N. Each system is different from scanning line, sound frequency and modulation system. If the TV systems are different, TV does not get a picture and a sound. TV systems are indicated in the rating plate on the lower case. e.g. Brazil Argentina Color System PAL PAL TV System M/M N/N Channel System US US

5.5MHz

4.43MHz

PAL PAL PAL/SECAM

-/I D/I B/G,H

UK China/UK CCIR

6 MHz 6.5 MHz / 6 MHz 5.5 MHz
4.43MHz 4.43MHz 4.25/4.40MHZ

G H I J K L M N P Q R S

PAL PAL PAL SECAM NTSC PAL PAL PAL PAL PAL PAL PAL PAL PAL PAL SECAM SECAM PAL PAL PAL PAL PAL PAL SECAM
M/M N/N B/G L/L M/M B/G,H B/B B/G,H B/G,H,I B/G,H,I B/G,H,I B/G,H B/G,H B/G,H B/G,H B/G,H B/G,H I/I I/I I/I I/I D/D D/K K1/-
US US ITALY France US CCIR Australia CCIR CCIR/UK CCIR/UK Italy/UK Australia CCIR ITALY New Zealand CCIR Morocco Angora Ireland UK South Africa China O.I.R.T F.O.T.

625 625

4.5 MHz 5.5 MHz 5.5 MHz 6.5 MHz 4.5 MHz 5.5 MHz 5.5 MHz 5.5 MHz 5.5 MHz / 6MHz 5.5 MHz / 6MHz 5.5 MHz / 6MHz 5.5MHz 5.5MHz 5.5MHz 5.5MHz 5.5MHz 5.5MHz 6.0MHz 6.0MHz 6.0MHz 6.0MHz 6.5MHz 6.5MHz 6.5MHz
3.58MHz 3.58MHz 4.43MHz 4.25/4.40MHz 3.58MHz 4.43MHz 4.43MHz 4.43MHz 4.43MHz 4.43MHz 4.43MHz 4.43MHz

Selector: I

4.25/4.40MHz 4.43MHz Selector: II

4.43MHz 4.25/4.40MHz

Selector: III

D/K M/M N/N K1/-

O.I.R.T US US F.O.T.
6.5MHz 4.5MHz 4.5MHz 6.5MHz
4.25/4.40MHz 3.58MHz 3.58MHz 4.25/4.40MHz Selector: M Selector: N

PAL PAL SECAM

SECAM Y PAL PAL PAL PAL SECAM SECAM PAL PAL PAL PAL SECAM
D/K B/G,H B/G,H B/G,H B/G,H B/G,H B/G,H I/I I/I I/I I/I L/L
O.I.R.T Australia CCIR Italy New Zealand CCIR Morocco Angora Ireland UK South Africa France
6.5MHz 5.5MHz 5.5MHz 5.5MHz 5.5MHz 5.5MHz 5.5MHz 6.0MHz 6.0MHz 6.0MHz 6.0MHz 6.5MHz
4.25/4.40MHz 4.43MHz Selector: I

4.25/4.40MHz

VHF, UHF VHF: Abbreviation for Very High Frequency. The sending out of radio waves at the rate of 30 to 300MHz, Producing good sound quality. UHF: Abbreviation for Ultra High Frequency. The sending out of radio waves at the rate of 300 to 3000MHz, Producing excellent sound quality.

Antenna VHF, UHF

Linear PCB

TU200 Tuner Q200 IF Amp.

IC200 Video Det. Sound Det. FM Det. AFT Circuit AGC Circuit VR Volume Control IC600 Audio Amp.

Speaker

Display ass'y
IC700 OSC. Display Control A-D Converter Auto-tuning Control

Common Drive

VR Brightness Control
IC800 Display Voltage Generator

Segment Drive

R o d A n t e nn a When the rod antenna is not properly adjustment, TV reception is not get a clear picture( picture moves up or down, disappears periodically, becomes fuzzy or blurred, is doubled, etc.). In this case, adjust angle and direction for best reception. Locations where TV reception is bad. Far away from broadcasting stations, among ferro-concrete structures or near mountains. Underground, in tunnels or in ferro-concrete buildings. Near high-tension wires, neon signs, or radio stations whose frequencies interfere. Near railroads, highways or airport. In trains or cars. -7-

Under poor reception conditions, the tuning indicator may continue to move without stopping because the auto tuner cannot detect weak broadcasts. In this case, use a commercially available external antenna or relocate the TV to a place where reception is better. The user usually damaged the rod antenna. We suggest that you stock this parts. Model CV-1 is used both as a earphone and an antenna. PCB Ass'y Linear PCB 1) Color tuner: TU200 Selects a desired radio wave and changes it to the video IF signal. 2) Video IF Amp.: Q200 Amplifies the video IF signal output from the tuner by 10 times. 3) Video Det./ Sound Det./ FM Det./ AFT/ AGC: IC200 Eliminates the carrier wave in the video IF signal, and pick up the video signal and the sound signal. Also, the sound signal is picked up from the sound IF signal by FM detection. Automatic fine tuning circuit for keeping the frequency of the oscillator in the tuner correct for best color picture by compensating for drift and incorrect tuning. Automatic gain control circuit for avoiding influence of receiving deterioration by wave strength. 4) Audio Amp.: IC600 Sound amplification. 5) Chroma Circuit: IC300 Generates the tricolor (red, green and blue) from the video signal. 6) Tuning voltage generator: IC500 Generates the tuning voltage from the tuning pulse (TU). PW PCB: Generates the power supply voltage. SUB PCB: Generates the power supply voltage. RD PCB: Selects a desired radio wave. Display Ass'y LCD Casio LCD television is used two type of LCD drive systems: HQM and Active matrix. 1) HQM ( Simple Matrix ) Scanning and segment transparent electrodes are arranged in closed way. To the scanning electrodes, the gate pulse is applied timesharing. The TV signal is changed into 4-bit or 3-bit data through A/D conversion (IC700), so that the TV signal can be handed with the LSI, and applied to the segment electrodes. Structure is simple and price is low, but contrast ratio is low. 2) Active Matrix Each picture element electrode is controlled by a transistor. To the gate electrodes, the gate pulse is applied timesharing, like the HQM. I f the gate pulse is applied, the transistors are in operation and voltage is applied between the picture electrodes and common electrodes and the liquid crystal reacts allowing the light to transmit. Structure is complicated and price is high, but contrast ratio is high.
(1) High Quality Matrix Y1 Y2 Y3 Y4 Xn
(2) Active Matrix Y1 X1 Y2 Y3 Y4

X1 X2 X3 X4 X5

Back Light: It produces light and allows the LCD to be seen. A fluorescent lamp is used this back light, and the life of this unit is to be 1,500 hours. Power Supply: 3-way power supply system. Batteries - AA-size or AAA-size (CV-1) dry batteries. Battery Life:
Type AlkalineLR6 (AM-3) Manganese R6 (UM-3) Life Approx.2 ~ 3 hours Approx.15 ~ 30 minutes
AD PCB 1) OSC/ A-D Converter/ Display Control/ Auto-Tuning Control: IC700 Converts the color signal into a digital signal. Also, generates the clock pulse for the display and controls the display. 2) Display voltage generator: IC800 Generates the display voltage. Back Light Placed it under the LCD unit and producing light that TV screen can be seen. A fluorescent lamp is used this back light. The life is to be 1,500 hours. New type of fluorescent lamp is to be 3,000 hours. The back light is consumption items, so even under guarantee replace it under charge basis. Power Supply There are 3-way power supply systems. 1) Batteries: AAA-size and AA-size (CV-1) We recommend to use alkaline batteries.The battery life is approx. 2 to 3 hours with alkaline battery, 15 to 30 minutes with manganese battery. The battery supplied with TV are test battery which have a shorter life span. Low battery power generates heat. Heat does not mean malfunction. 2) AC adaptor There are three type of AC adaptors: 6V, 9V and 12V. The optional AC adaptor is supplied from our sales department. 3) Car adaptor There are three type of Car adaptors: 6V, 9V and 12V. The optional car adaptor is supplied from our sales department. -9-

DC IN: External power source jack. Insert the plug of the AC adaptor or the car adaptor into this jack. EXT/ANT.: External antenna jack. Insert the plug of the optional car antenna into this jack. Connect the optional antenna adaptor AS-35S to your outdoor antenna or the optional RF cord CF-13 to your VCR. AUDIO/VIDEO: Audio video jack. Connect the optional Audio video cable cord AV-C1 to your VCR.
Tuner The tuner selects and amplifies the incoming AM video-modulated and FM sound-modulated signals and concerts them to the inter mediate-frequency signals required by the IF amplifiers. Picture carrier Antenna fv Amplify the channel frequencies Input Circuit Select specific channel Power supply voltage BV BU BM Local oscillator fosc Local oscillator frequency RF Amp. Convert the channel frequencies to intermediate frequencies Picture IF = fosc - fv = 45.75MHz (US channel) Sound IF = fosc - fs = 41.25MHz (US channel) Tuning Circuit Mixing Circuit VIF

CIRCUIT OPERATION

fs Sound carrier
AGC The Automatic Gain Control system maintains a substantially constant video detector picture output by applying an automatically varying dc bias voltage to the RF. In basic principle, the AGC system in a TV receiver is similar to AVC systems in radio receivers- it provides a constant-amplitude signal.

Field-strength is weak

BS VHF low and high channels selecting voltage. VHF(L) : Approx. 20V VHF(H): Approx. 0V
B T Tuning voltage input terminal. A channel corresponding to the direct voltage to this terminal is selected, and frequency conversion is performed.
TV-100B VHF(L) VHF(L) VHF(H) UHF UHF 2CH 7CH 14CH 1.0-2.8(V) 6.4-8.4(V) 2CH 5CH 6CH 17.2-18.8(V) 4CH TV-100C 1.3-3.3(V) 6.5-8.5(V) 6.1-8.1(V) 0.9-2.3(V)
VHF(H) 13CH 17.2-18.8(V) 12CH 17.2-18.8(V) 1.0-3.4(V) 21CH 69CH 22.4-23.6(V) 69CH 24.4-25.6(V)

Field-strength is strong

Tuner Voltage BV: Power voltage for inner VHF circuit. BU: Power voltage for inner UHF circuit. BM: Power supply for internal mixer.
VHF(L) BV Approx. 4V 0V Approx. 4V 0 - 25V Approx. 20V 1.0 - 3.0V BU BM BT BS VHF(H) Approx. 4V 0V Approx. 4V 0 - 25V 0V 1.0 - 3.0V UHF 0V Approx. 4V Approx. 4V 0 - 25V 0V 1.0 - 3.0V

Video IF Amp.

Video DET

Video Amp.

AGC for Tuner

AGC for IF

AGC Amp. AGC voltage

AGC DET

Noise elimination

AGC voltage

I C 0 V i d e o D E T. , S o u n d D E T. , F M D E T. , A GC , M U T E. 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 and controlled its volume by MUTE voltage. To IC300 SIF trap
Video signal + Sound IF SIF trap removes the sound IF. Discriminator Picks up the sound signal.
SYNC. SEP Picks up the synchronizing pulse from the video IF signal. IF AGC DET. RF AGC Video DET.

Sound signal

FM DET.

Video AMP.

ATT Buffer Limiter

1st and 2nd AMP.

I F signal input VIF V i d e o detection
SIF filter picks up the SIF from video signal.

Carrier wave

SIF Demodulation Coil connected to pin no. 19 and 20 determines the tuning point of the LLD detection, and must be matched with the intermediate frequency.
Automatic f i n e tuning Model AFT voltage AFT block generates the AFT voltage TV-100 2.5 +/-0.2V (direct voltage ) with a difference of TV-480 1.7 +/-0.2V frequency between the IF and input signal from the tuner. Audio Signal
Video Amplifier SIF filter Sound Takeoff

Video signal

Sound IF
SIF filter removes the fs-fv MHz sound component from sound IF signal.
Limits the amplitude of its output signal to some predetermined threshold level.

Limiter-Amplifier

The sound is cut off during tuning. Audio signal is cut when pin no. 14 receives GND level.

ATT Audio Amplifier

Picks up the sound signal from FM modulated signal.
U.S.A SIF filter Discriminator SIF trap CCIR
FM detection (Discriminator)

U.K. China

4.5MHz 5.5MHz 6.0MHz 6.5MHz 4.5MHz 5.5MHz 6.0MHz 6.5MHz 4.5MHz 5.5MHz 6.0MHz 6.5MHz
I C 0 Chroma Circuit ( N T S C ) Generates the tricolor of red, green and blue from the video signal. Y/C Separator Video signal B a n d pass A mp. is the amplified composite color video signal. Color signal
Burst Amp. separates the color sync from the composite video signal. Color sub carrier Trap

Luminance signal

Band pass filter

Color adjust

Hue adjust Contrast adjust
Contrast Adjust Color adjust Y mixer B Amp. Blue

Band Amp.

Sync signal

Burst Amp. Hue adjust

B-Y demodulation

Burst Generator

G-Y Matrix

Y mixer G Amp.

Automatic Chroma Control

Color Killer

Automatic Phase Control

Sub carrier OSC

R-Y demodulation

Red Y mixer R Amp.

Automatic Chroma Control ACC is to provide automatic gain control for the chroma amplifies.This circuit is keeping the chroma and burst signals at a constant level. Color Killer The color killer keeps the band pass amplifier cutoff in the absence of a color signal.
APC Reinserts a sub carrier signal with exactly the correct phase and frequency by synchronizing with the transmitted color-burst signal.
DEMODULATION The B-Y and R-Y demodulators are each synchronized essentially to sample the resultant chrominance signal EC and produce the respective B-Y and R-Y voltage. After demodulation, the B-Y and R-Y signals enter the matrix stage. The two color signals combine in the G-Y matrix which produces the resultant G-Y color signal, and output signals (B-Y, R-Y and G-Y) combine with the luminance signal at the mixer , then outputs proportional values of red, blue, and green.
I C 0 Chroma Circuit ( P A L ) Generates the tricolor of red, green and blue from the video signal. Y/C Separator
Chroma Trap 4.43MHz Band pass filter
Video signal Color signal
SYNC SEP. Luminance signal

Contrast adjust

PIX CTR
Y-OUT Contrast adjust Blue

Chroma OUT PAL/SECAM SW

B Matrix

Green G Matrix G-OUT

ACC DET

Red R Matrix R-OUT

Burst GP 0 and 180 Killer PAL-SW 90 Automatic Phase Control

R-Y DEM

B-Y DEM
The point that NTSC is different from PAL in a part of frame of bold lines
PAL is basically the same as NTSC. PAL is different from NTSC in the way of the color signal transmission. The phase of B-Y signal is fixed 90 degree. The phase of R-Y signal changes at 0 and180 degree on every horizontal scanning line. The 4.43MHz sub carrier is used to transmit color information.
I C 0 Chroma Circuit ( P A L / S E C A M ) Generates the tricolor of red, green and blue from the video signal.
Y/C Separator Chroma Trap 4.43MHz Band pass filter Sync SEP. Luminance signal Contrast adjust

Color signal

Contrast adjust Blue B Matrix B-OUT Green

PIX ACC Chroma OUT

PAL/SECAM SW ACC DET Sync signal Burst GP

G Matrix

G-OUT Red
R Matrix 0 and 180 PAL-SW 90 Sub carrier OSC
R-OUT R-Y B-Y Automatic Phase Control

Killer

Bell filter 4.28MHz

Horizontal sync SECAM

line identify ID F/F

Blanking signal

B-Y signal Quadrature 4250000Hz coil 4.25MHz 4.25MHz

Cleaning

Limiter
line change over interlock switch SECAM direct to switch(non-delayed signal) SW Gate SW

limits the amplitude

Picks up the SECAM color signals (B-Y, R-Y) by FM detectors Sub carrier frequency R-Y signal 4406350Hz

R-Y DEM 4.406MHz

One delay line through one delay line(delayed signal)

Quadrature coil 4.4MHz

It is difference of SECAM , NTSC and PAL that the frequency of R-Y and B-Y signal are demodulated and transmitted reciprocally in order on every line. The demodulation of signal SECAM is separated from two systems. One system is led direct to the line change over interlock switch circuit, another system is led to the switch circuit through one delay line. The switch circuit changes over the delayed signal of a term scanning line and non-delayed signal, takes out two color different signal. By detecting in each FM, R-Y and B-Y signal are gotten. -15-
IC400 Tuning Voltage Generators IC400 has 3 circuits for converting pulses to voltages, selects one of VHF-L, VHF-H or UHF, and causes the tuning voltage to be output from OUT terminal.
OUT U/V H/L SW on L L H H L H L H S3 S2 S1 S6 S5 S4 Current Source S2, S5 S3, S6 S1, S4 S1, S4 TU SW on L H S7 S8 S8 S7 BT IN

BS GEN. CODE CONV.

Vref GEN.

UHF VCC

H/L BS
U/V UHF / VHF channels switching signal. Input 4V with setting the select switch to UHF. H/L VHF low / high channels switching signal. GND level when the indicator is VHF low channel. Approx. 4V when the indicator is VHF high and UHF channel
VHF low / high channels switching signal. Approx. 20V when the indicator is at VHF low channel.
TU Tuning pulse being output from IC700.

TU pulse

BT Tuning voltage. Tuning pulse is converted into a DC voltage by the IC400, and applied to the tuning voltage to the tuner.

BT voltage

U/V VHF L GND VHF H GND UHF Approx.4V
H/L GND Approx.4V Approx.4V

BS GND GND

BT Approx.0 ~ 20V Approx.0 ~ 20V
Approx.20V Approx.0 ~ 20V
When the Up or Down buttons is pressed, TU pulse becomes gradually narrower, and the tuning voltage BT is also gradually decreases.
VSS2 TE1 TE2 TE3 TE4 TE5TE6 M6 M5 M4 M3 M2 M1 AFT
AD2 AD1 B G R RLL VDD2 RHH

Test Control A/D

Mode Control

Key Switch Control

KDB KCB AVB UHF
Frequency Divider Channel Bar Control
Sweep Control Tuning Voltage UP/DOWN Counter

VLB Synchronism Judgment

M7 M8 M9 M10 PSi VSS1
Pulse Width Modulation D/A Frequency Separator

VDD1 C-S PD OSC1 OSC2

Phase Comparator Data Output Vertical Positioning Control Horizontal Positioning Control Frequency Divider Oscillator
CDB CFB CNB ECB SNB SCB STB HDB
SignalName D1 ~ D6 SNB CDB CFB CNB SCB STB ECB CK1, CK2 PD C-S HDB VDD1 MTB TU
Function Displaydata output terminal. Data latch signal. Scanning start signal. Voltage changeover signal. Scanning Signal shift lock signal. Brightnessmodulation pulse control. Sampling start signal. Control the segment drive terminal. "H" level during no display. Clock pulse output terminal. Clock pulse adjustment terminal. Sync pulseinput. HorizontalSync signal input. VDD voltage input. Mute control terminal. Tuning control pulse output.
SignalName VLB UHF AVB KCB KDB AFT M1 ~ M10 TE1 ~ TE6 R, G, B RLL RHH PS1 VSS1 output.
Function VHF High/Low channel select signal VHF/UHF selectsignal. Key input. Key input. Key input. AFT voltage input terminal. Mode select signal input terminal. Test terminal. Color signal. Low level voltage input terminalof video signal. High level voltage input terminalof video signal. Mode control signal. Power supply voltage input.
OSC1, OSC2 Oscillatorcontrol terminal.

Tuning Operation (NTSC)

UP or Down button
PD OSC1,OSC2 Horizontal Positioning Control Vertical Positioning Control

TO LCD

Oscillator
Synchronism Judgment A/D Convertor Data Output
Frequency Separator Phase Comparator

Sweep Control

Channel Bar Control VCC1 Back Light Circuit Back Light
Pulse Width Modulation TU BU
MTB Tuning voltage control VLB H/L H/L Mute Control Power Switch UHF UHF or VHF VHF

Power Supply Circuit

BS Generator

BT Generator

Batteries or AC Adaptor Antenna
VHF/UHF RF AMP. UHF Tuning Circuit Local Oscillator Local Oscillator IF AGC

VHF/UHF Input Circuit

VHF Tuning Circuit

TUNER IC200

UHF Mixing Circuit

VHF Mixing Circuit

IF AMP.

SAW Filter

Video DET.

2nd AMP.

1st AMP.

SIF Filter

FM DET

SIF Trap

SYNC. SEP

Buffer

3.58MHz Trap

Contrast Adjust

Color Adjust

B-Y Demodulator

Y Mixer Blue AMP.

Band pass Filter

Band AMP.

Burst AMP.

Hue Adjust

Y Mixer Green AMP.

R-Y Demodulator

Y Mixer Red AMP.

3.58 MHz OSC
Adjustment Casio gives another through adjustment before TVs are put on the market. There's usually no need for you to adjust the TVs except VCC voltage setting when repaired the power supply circuit and VCOM adjustment whenever replaced the TFT LCD. The other adjustments, it is necessary to have the expensive equipment's. When appropriate equipment's are not available, we recommend to replace the Linear PCB ass'y.
The full details of adjustments, refer to each of service manuals. Main Adjustment Points VCC Voltage Setting Outline Set the voltage VCC. If set value is wrong, malfunction or increasing consumed current. Be sure to adjust it. Video Detection Coil Adjustment No reception is possible at all or the sensitivity is extremely bad when replaced IC200 or video detection coil, be sure to adjust the video detection coil. AFT Coil Adjustment No reception is possible at all or the sensitivity is extremely bad when replaced IC200 or AFT coil, be sure to adjust the AFT coil. Equipment Power supply Voltmeter Power supply Pattern generator Signal generator Oscilloscope Low-pass filter Power supply Pattern generator Signal generator Oscilloscope Voltmeter Power supply Pattern generator Signal generator Voltmeter IF levelmeter Power supply Pattern generator Signal generator Oscilloscope Power supply Pattern generator Signal generator Oscilloscope Power supply Pattern generator Signal generator Oscilloscope IF levelmeter Power supply Frequency Counter Power supply Pattern generator Signal generator Oscilloscope Photo diode

PD Voltage Adjustment

No synchronization is gained.

Contrast Adjustment

Make this adjustment when contrast is not good.

Tint Volume Adjustment

When replacing IC300 or tint volume, be sure to adjust the tint volume.

AGC Adjustment

No reception is possible at all or the sensitivity is extremely bad when replaced T200 or IC200, be sure to adjust the video detection coil.
Free-Running Frequency Adjustment VCOM Adjustment (TFT LCD only)
No synchronization is gained. Make this adjustment whenever replacing the LCD or when the LCD is flickered.
TROUBLESHOOTING 1. No power

Is the waveform at pin 19 and 20 of IC200 like that shown Fig. 3? 20s

Check the poor

soldering on all line of IC200 and MSC1169. Replace IC200.
0.5V Is AFT (at pin no. 17 of IC200) voltage 0 to 4V While Indicator moves? Figure 2 10mV Figure 3 Replace IC200.
Varies between 20 to 50mV
2V Figure 4 Is SyOUT (at pin no. 23 of IC200) like that shown Fig. 4?

Replace H300.

YES NO
Figure 5 Is the waveform of R, G and B like that Fig. 5 when the indicator passes the receiving channel ?

Is an AV jack OK?

Is the waveform of H300 like that shown Fig. 6?

NO YES

0.2V Figure 6

Replace AV jack.

Check the circuit between IC200 and IC300. Replace IC300.

5s Replace MSC1169.

Check BT of tuner voltage in a channel of VHF.

1V Figure 7

Is BT voltage 0 to 21V at VHF channel?
Is the waveform YES at pin no. 11(TU) of MSC1169 like that shown in Fig.7?
Does 4V appear at pin no. 9 (H/L) of MSC1169 at UHF?
Is the tuner voltage AGC 1.0 to 1.2V?

YES Check the circuit

between MSC1169 and IC700. Replace IC700. Replace tuner. Check the circuit between switch and MSC1169. Replace Switch.
IS H/L 4V at VHF L channel?
IS H/L voltage GND level at VHF H channel?

Replace MSC1169.

NO NO Check the circuit between
MSC1169 andIC700. Replace IC700.
Do C-S, AFT and R-G-B pulse appear on IC700?
Check the circuit between IC300 and IC700.
Is the waveform at pin no. 17 of IC700 (OSC) like that shown in Fig. 8?

5V Figure 8

Check the poor soldering on OSC b lock. Replace IC700.

Trouble example

TV-7 Symptoms No picture Causes FL replaced Temperature fuse replaced Power switch replaced Fuse replaced Battery replaced Battery replaced Battery replaced Defective speaker

No sound No tuning

TV-100 Causes FL replaced LCD replaced DC jack replaced Fuse replaced Poor soldering No sound Battery replaced Speaker replaced Poor soldering on IC Bright volume doesn't work Defective R825 Picture all green Short circuit joint on lead of capacitor C105 Indicator does not stop Poor soldering joint on lead of capacitor C303 Poor soldering joint on terminal pin 17 of IC700 Broken resistor R703 Defective capacitor C205 & C808 Defective F200 No tuning when the RF signal is Defective IC200 under 55dB Tuning is OK, but erratic display Defective capacitor C205 & C808 Indicator does not stop Defective capacitor C205 & C808 when the RF signal is strong No picture Symptoms
TV-160 Symptoms No picture Fuse replaced Battery replaced LCD replaced Speaker replaced Battery replaced LCD replaced Speaker replaced LCD replaced Speaker replaced LCD replaced FL replaced Causes
No sound Indicator does not stop Specific channel does not receive
Poor reception or picture dark

SCHEMATIC DIAGRAM & WAVEFORMS NTSC

AV Jack

IC200 Video DET., Sound DET., FM DET., AGC, AFT and Mute
BU EXT Jack UHF input circuit UHF RF Amp. UHF tuning circuit UHF local oscillator UHF mixing circuit VHF input circuit VHF RF Amp. VHF tuning circuit VHF mixing circuit IF output BS(0/20V) VHF local oscillator Power switch BU(4V) BV(4V) OUT IC400 Tuning voltage generator AMP. S3 S2 S1 S6 S5 S4
U/V H/L SW ON L L S2, S5 L H S3, S6 H L S1, S4 H H S1, S4 TU SW ON L S7 H S8
3 AFT 5 SYNC. SEP 1 IF Amp. 1 SAW filter 2 F200 IF AGC DET. VIDEO DET. LLD 2
4.5MHz FM detection 4.5MHz

6 Speaker

FM DET. ATT VIDEO AMP.
Amp. Earphoen Jack BUFFER
2nd AMP. RF AGC (Forward) 1st AMP.

BT(0 21V)

LIMITER
BV VCC2 AGC 1.0 3.0V SIF filter 4.5MHz
IC700 OSC, A-D converter, Display control Auto-Tuning control
S8 AMP. S7 BT VSS2 TE1 TE2 TE4 TE6 TE3 TE5 M6 M5 M4 M3 M2 M1 AFT Key switch control KDB KCB AVB UHF 3V

Test control

Mode control

AFT control

CODE CONV. U/V Power supply circuit H/L

BS GEN. BS 12

Current Source Vref GEN. TU Vref
A/D Frequency divider Channel bar control Sweep control Mute control Synchronism judgment Frequency separator MTB
Tuning voltage Up/Down counter Pulse width modulation D/A

Fuse Power Jack

IC300 Croma circuit

FSC APC ACC TINT CIN

11 G R 10 B C-SY Mode control Phase comparator Data Output Vertical positioning control Horizontal positioning control Frequency divider C-S PD VDD1 Oscillator OSC1 OSC2 IC702 D1D2 D3 CDB SCB CNB SNB HDB STB CK1 CK2
CK1 CK2 STB SNB S1 C1 D1~D3 S359
ACC Color R-Y DET. Batteries APC TINT BURST GATE
MATRIX (CONTRAST) G-Y DET. B-Y DET.
GATE GEN. VCO VXOUT 7 KILLER YIN 8 PIX CLAMP Cont OUT 9 BGPW

D4 D5D6 VC 4V

CDB CFB CNB

X'tal VXOF Killer F KO

PIX Cont

CK1 CK2 STB SNB D4~D6

BU EXT Jack UHF input circuit UHF RF Amp. UHF tuning circuit UHF local oscillator UHF mixing circuit VHF input circuit VHF RF Amp. VHF tuning circuit VHF mixing circuit IF output BS(0/20V) VHF local oscillator Power switch BU(4V) BV(4V) BV VCC2 AGC 1.0 3.0V BT(0 21V)