Apex at2408s schematic

SERVICE MANUAL

FILE NO. SM-CTV-O-044

COLOR TELEVISION

SERVICE MANUAL

MODEL NO. CHASSIS NO. CH-10C1(S)

AT2408S/AT2408

Please read this manual carefully before service

PRINTED IN CHINA.MAY.2003 ©

SERVICE MANUAL

CONTENTS

SAFETY INSTRUCTIONS...........................................................................................1

SPECIFICATIONS .......................................................................................................2

KDEY ICS AND ASSEMBLIES....................................................................................3

SYSTEM BLOCK DIAGRAMS.....................................................................................4

IC DATA AND WAVEFORMS OF KEY POINTS ..........................................................5

CIRCUIT ADJUSTMENTS...........................................................................................5

SET-UP ADJUSTMENTS ............................................................................................5

SERVICE MODE AND BUS DATA ..............................................................................5

TROUBLESHOOTING FLOW CHARTS......................................................................7

SERVICE SPARE PARTS LIST.................................................................................13

APPENDIX

1. CIRCUIT DIAGRAM

2. FINAL WIRING DIAGRAM

3. FINAL ASSEMBLY DIAGRAM

4. PRINTED CIRCUIT BOARD DIAGRAMS

SERVICE MANUAL

SAFETY INSTRUCTIONS

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY

RADIATION PRECAUTION”, “SAFETY PRECAUTION” AND “PRODUCT

SAFETY NOTICE” INSTRUCTION BELOW.

X-RAY RADIATION PRECAUTION

1. The EHT must be checked every time the TV is serviced to ensure that the CRT does not emit X-ray

radiation as result of excessive EHT voltage. The nominal EHT for this TV is 27.5KV at zero beam

current (minimum brightness) operating at AC 120V. The maximum EHT voltage permissible in any

operating circumstances must not exceed 30KV. When checking the EHT, use the High Voltage

Check procedure in this manual using an accurate EHT voltmeter.

2. The only source of X-RAY in this TV is the CRT. To prevent X-ray radiation, the replacement CRT

must be identical to the original fitted as specified in the parts list.

3. Some components used in this TV have safety related characteristics preventing the CRT from

emitting X-ray radiation. For continued safety, replacement component should be made after

referring the PRODUCT SAFETY NOTICE below.

SAFETY PRECAUTION

1. The TV has a nominal working EHT voltage of 27.5KV. Extreme caution should be exercised when

working on the TV with the back removed.

1) Do not attempt to service this TV if you are not conversant with the precautions and procedures for

working on high voltage equipment.

2) When handling or working on the CRT, always discharge the anode to the TV chassis before

removing the anode cap in case of electric shock.

3) The CRT, if broken, will violently expel glass fragments. Use shatterproof goggles and take extreme

care while handling.

4) Do not hold the CRT by the neck as this is a very dangerous practice.

2. It is essential that to maintain the safety of the customer all power cord forms be replaced exactly as

supplied from factory.

3. Voltage exists between the hot and cold ground when the TV is in operation. Install a suitable

isolating transformer of beyond rated overall power when servicing or connecting any test

equipment for the sake of safety.

4. Replace blown fuses within the TV with the fuse specified in the parts list.

5. When replacing wires or components to terminals or tags, wind the leads around the terminal before

soldering. When replacing safety components identified by the international hazard symbols in the

circuit diagram and parts list, it must be the company-approved type and must be mounted as the

original.

6. Keep wires away from high temperature components.

SERVICE MANUAL

SAFETY INSTRUCTIONS (continued)

PRODUCT SAFETY NOTICE

Many electrical and mechanical components in this chassis have special safety-related characteristics.

These characteristics are often passed unnoticed by a visual inspection and the X-ray radiation

protection afforded by them cannot necessarily be obtained by using replacements rated at higher

voltages or wattage, etc. Components which have these special safety characteristics in this manual

and its supplements are identified by the international hazard symbols in the circuit diagram and parts

list. Before replacing any of these components read the parts list in this manual carefully. Substitute

replacement components which do not have the same safety characteristics as specified in the parts

list may create X-ray radiation.

PRECAUTIONS

Power Sources-The TV set should be operated only from the type of power source indicated on the TV set or as indicated in the Service Manual. If you are not sure of the type of powe supply in your home, consult your sales person or your local power company. For TV sets designed to operate from battery power, or othe sources, refer to the operating instructions.

Grounding or Polarization-Do not defeat the safety purpose of the polarized o grounding-type plug. A polarized plug has two blades with one wider than the other. grounding-type plug has two blades and a third grounding prong. The wide blade or the third prong is provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

Wide blade Lame large Cuchilla ancha

Alternate Warnings-A three wire grounding type plug-a plug having a third (grounding) pin. This plug will only fit into grounding type powe outlet.

Water and Moisture Warnings-Do not use the TV set near water-for example, near a bath tub, wash bowl, kitchen sink, or laundry tub; in a wet basement; or near a swimming pool; and the like.The TV set shall not be exposed to dripping or splashing and no objects filled with liquids, such as vases, shall be placed on the TV set.

Ventilation-Slots and openings in the cabinet are provided for ventilation and to ensure reliable operation of the TV set and to protect it from overheating, and these openings must not be blocked or covered. The openings should neve be blocked by placing the TV set on a bed, sofa, rug, or other similar surface. This TV set should not be placed in a built-in installation such as a bookcase or rack unless proper ventilation is provided or the manufacturer have been adhered to.

s instructions

SERVICE MANUAL

SPECIFICATIONS

Television system:

Channel coverage:

Channels preset:

Antenna input:

Picture tube;

Max. audio output;

Power source;

Weight:

Dimensions(W/H/D):

Packing dimensions(W/H/D):

Rated power consumption:

NTSC-M

VHF 2

UHF 14

CABLE TV: MID BAND (A-8

A-1, A I)

SUPER BAND (J

HYPER BAND (AA

ULTRA BAND (65

181

(unbalanced)

Effective screen dimensions: 478mm×363mm (18.82×14.29 in.)

5W×2 (for AT2408 only); 5W+5W (for AT2408S only)

120Vac 60Hz

31.5kg (69 lbs) (Approx.)

660×522×458mm (25.98×20.55×18.03 in.) (Approx.)

740×610×545mm (29.13×24.02×21.46 in.) (Approx.)

125W

Designs and specifications are subject to change without notice.

KEY ICS AND ASSEMBLIES

ZZ, AAA, BBB)

94, 100 125)

Table 1 Key ICs and Assemblies

Serial No. Position No. Model No. Function Description

1 N301 OM8839PS/TDA8843-N2 Small signal processor

2 N401 TDA8350Q Vertical output circuit

3 N402 LM317 Tri-terminal regulator

4 N601 TDA7057AQ Sound power amplifier

5 N001 CH04T1002/CH04T1009 Microcontroller

6 N002 AT24C04 EEPROM

7 N811 TDA4605 Switching power control circuit

8 NY01 TDA6107Q Video amplifier

9 DS01 HEF4052 Analog switch circuit

10 DS02 HEF4053 Analog switch circuit

11 N606 TDA9859 Audio processor

12 U101 TDQ-6F2M2 Tuner

Note: TDA9859 (N606) is not available in AT2408.

SERVICE MANUAL

SYSTEM BLOCK DIAGRAMS

Fig.1 Block Diagram for CH-10C1(S) Remote Control Structur

SERVICE MANUAL

SYSTEM BLOCK DIAGRAMS

(continued)

Fig. 2 Structure Block Diagram for CH-10C1(S) Chassis

SERVICE MANUAL

SYSTEM BLOCK DIAGRAMS

Fig. 3 Block Diagram for CH-10C1(S) Supply Voltage System

(continued)

SERVICE MANUAL

SYSTEM BLOCK DIAGRAMS

(continued)

Fig. 4 Block Diagram for CH-10C1(S) Video Signal Processor

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

TDA 4605

Control IC for Switched-Mode Power Supplies Using MOS-Transistor

1. Features

Fold-back characterisitics provides overload protection for external

components

Burst operation under secondary short-circuit condition implemented

Protection against open or a short of the control loop

Switch-off if line voltage is too low (undervoltage switch-off)

Line voltage depending compensation of fold-back point

Soft-start for quiet start-up without noise generated by the transformer

Chip-over temperature protection implemented(thermal shutdown)

On-chip ringing suppression circuit against parasitic oscillations of the

transformer

AGC-voltage reduction at low load

2. Block Diagram

Fig. 11

3. Refer to Table 3 about Functions and Data of the IC’s Each Pin.

Fig. 10

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS (continued)

CH04T1002/ CH04T1009

1. Terminal Assignment Layouts

Fig. 12 CH04T1002/ CH04T1009 DIP42S Terminal Assignment Layoutd

Fig. 13 CH04T1002/ CH04T1009 QIP48E Terminal Assignment Layout

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS (continued)

CH04T1002/ CH04T1009 (continued)

2. Terminal Function

Table 2 Terminal Function Table

Terminal I/O Function Description Option Format

VSS - Negative power supply

XT1 1 Input terminal for crystal oscillation

XT2 O Output terminal for crystal oscillation

VDD - Positive power supply

RES I Reset terminal A

FILT O Charge-pump ouput terminal N

CVIN I

VS I

HS I

R O

G O

B O Blue (B) output terminal of RGB imagee

I O Intensity (I) output terminal of RGB image

BL O

Part 0

P00-p07

Port 1

P10-P17

Port 6

Image signal input terminal (available only in CH04T1002) Vertical synchronization signal input terminal

Horizontal synchronization signal input terminal

Red (R) output terminal of RGB image

Green (G) output terminal of RGB image

Fast blanking control signal Switch TV image and caption/OSD image signal

8-bit input/output port Input/output can be specified in nibble unit

I/O

Other functions: Hold release input Internal input

8-bit input/output port Each bit can be independently programmable Other functions:

P10 SIO0 data output P11 SIO0 data input/bus input/output P12 SIO0 clock input/output P13 PWM1 output P14 PWM2 output P15 PWM3 output P17 Timer 1(PWM) output

4-bit input/output port Each bit can be independently programmable Other functions:

P60 IIC0 data input/output P61 IIC0 clock output P62 IIC1 data input/output P63 IIC1 clock output

Pull-up resistor provided/not provided

Output format

CMOS/Nch-OD

Output format

CMOS/Nch-OD

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

(continued)

CH04T1002/CH04T1009 (continued)

Terminal I/O Function Description Option Format

P70

P71-P73

Port 7

P71-P73

I/O

4-bit input/output port

Each bit can be independently

programmable

Other functions:

P70

P71 INT1 input/HOLD release input P72 INT2 input/timer 0 event input

P73

Interrupt receiver format vector address

INTO

INT1

INT2

INT3

INTO input/HOLD release input /Nch-Tr. output for watchdog timer

INT3 input (noise rejection filter attached input)/timer 0 event input

Rising Falling

yes

Rising/ Falling

yes

H level L level Vector

yes

03H

0BH

13H

1BH

Port 8

P83

P84-P87

Port options can be specified independently for each bit.

The programmable pull-up resistors are provided, depending on whether CMOS or Nch-OD (Nch

open drain ) is selected as the port 1 option.

3. Refer to Table 3 about Functions and Data of the IC’s Each Pin.

I/O

1-bit input port

(P83 is set only in CH04T1002)

4-bit input/output port(P84-P87)

Each bit can be independently

programmable

Other function:

AD converter input port

P83

P84-P87

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

EEPROM AT24C04

1. Features

Data EEPROM internally organized as 512 bytes and 32 pages×16 bytes Low power CMOS Vcc=2.7 to 5.5V operation

Two wire serial interface bus I2C-Bus

compatible

Filtered inputs for noise suppression with Schmitt trigger Clock frequency up to 400 kHz High programming flexibility

-Internal programming voltage

-Self timed programming cycle including erase

-Byte-write and page-write programming between 1 and 16 bytes

-Typical programming time 6 ms(<10ms) for up to 16 bytes High reliability

-Endurance 10

-Data retention 40 years

-ESD protection 4000 V on all pins 8 pin DIP/DSO packages Available for extended temperature ranges

-Industrial

-Automotive

3. Block Diagram

cycles1)

-40 to +85

-40 to +125

2. Pin Configuration

4. Refer to Table 5 about Functions and

Data of the IC’s Each Pin

(continued)

Fig. 14

Fig. 15

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

OM8839PS/TDA8843-N2

I2C-bus Controlled PAL/NTSC/SECAM TV Processors

1. Features

The following features are available in all IC

·Multi-standard vision IF circuit with an alignment-free PLL demodulator without external components

·Alignment-free multi-standard FM sound demodulator (4.5 MHz to 6.5 MHz)

·Audio switch

·Flexible source selection with CVBS switch and Y(CVBS)/C input so that a comb filter can be applied

·Integrated chrominance trap circuit

·Integrated luminance delay line

·Asymmetrical peaking in the luminance channel with a (defeatable) noise coring function

·Black stretching of non-standard CVBS or lumina-nce signals

·Integrated chroma band-pass filter with switchable centre frequency

·Dynamic skin tone control circuit

·Blue stretch circuit which offsets colours near white towards blue

·RGB control circuit with “Continuous Cathode Calibration” and white point adjustment

·Possibility to insert a“blue back” option when no video signal is available

·Horizontal synchronization with two control loops and alignment-free horizontal oscillator

·Vertical count-down circuit

·Vertical driver optimised for DC-coupled vertical output stages

C-bus control of various functions

·I

2. General Description

The various versions of the TDA 884X/5X series are I2C-bus controlled single chip TV processors which are intended to be applied in PAL, NTSC, PAL/NTSC and multi-standard television receivers. The N2 version is pin and application compatible with the N1 version, however, a new feature has been added which makes the N2 more attractive. The IF PLL demodulator has been replaced by an alignment-free IF PLL demodulator with inter-nal VCO (no tuned circuit required). The setting of the various frequencies (33.4,

33.9,38, 38.9, 45, 75 and 58.75 MHz) can be made via the I Because of this difference the N2 version is compatible with the N1, however, N1 devices cannot be used in an optimised N2 application. Functionally the IC series is split up in 3 categories, viz:

·Versions intended to be used in economy TV receivers with all basic functions (envelope: S-DIP 56 and QFP 64)

·Versions with additional features like E-W geometry control, H-V zoom function and YUV interface which are intended for TV receivers with 110° picture tubes (envelope: S-DIP 56)

·Versions which have in addition a second RGB input with saturation control and a second CVBS output (envelope: QFP 64) The various type numbers are given in the table below.

(continued)

C-bus.

3. Survey of IC Types

Envelope S-DIP 56 QFP 64

TV receiver category Economy Mid/High end Economy Mid/High end

PAL only TDA 8840 TDA 8840H

PAL/NTSC TDA 8841 TDA 8843 TDA 8841H

PAL/SECAM/NTSC TDA 8842 TDA 8844 TDA 8842H TDA 8854H

NTSC only TDA 8846/46A TDA 8847 TDA 8857H

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

OM8839PS/TDA8843-N2 (continued)

4. Block Diagram

(continued)

Fig .16 Block Diagram “Economy Versions” (S-DIP 56 Envelope)

5. Refer to Table 6 about Functions and Data of the IC’s Each Pin.

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

TDA8350Q

DC-coupled Vertical Deflection and East-West

Output Circuit

1. Features

Few extemal components

Highly efficient fully DC-coupled vertical output

bridge circuit

Vertical flyback switch

Guard circuit

Protection against

- short-circuit of the output pins

- short-circuit of the output pins to Vp

3.Block Diagram

High EMC immunity due to common mode

inputs

Temperature (thermal) protection

East-West output stage with one single

conversion resistor.

2. General Description

The TDA8350Q is a power circuit for use in

90° and 110° colour deflection systems for

field frequencies of 50 to 120 Hz. The circuit

provides a DC driven vertical deflection output

circuit, operating as a highly efficient class G

system and an East-West driver for sinking the

diode modulator current.

(continued)

Fig. 17 Block Diagram

4. Refer to Table 7 about Functions and Data of the IC’s Each Pin.

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

(continued)

TDA7057AQ

2×8W Stereo BTL Audio Output Amplifier with DC Volume Control

1. Features

·DC volume control

·Few external components

·Mute mode

·Thermal protection

·Short-circuit proof

·No switch-on and switch-off clicks

·Good overall stability

·Low power consumption

·Low HF radiation

·ESD protected on all pins.

3. Block Diagram

General Description

The TDA7057AQ is a stereo BTL output amplifier with DC

volume control. The device is designed for use in TVs and

monitiors, but is also suitable for battery-fed portable

recorders and radios.

issing Current Limiter (MCL)

A MCL protection circuit is built-in. The MCL circuit is

activated when the difference in current between the output

terminal of each amplifier exceeds 100 mA (typical 300

mA). This level of 100 mA allows for single-ended

headphone applications.

Fig. 18 Block Diagram

4. Refer to Table 8 about Functions and Data of the IC’s Each Pin.

SERVICE MANUAL

IC DATA AND WAVEFORMS OF KEY POINTS

TDA6107Q

Triple Video Output Amplifier

1. Features

·Typical bandwidth of 5.5 MHz for an output

signal of 60 V (p-p)

·High slew rate of 900 V/S

·No external components required

·Very simple application

·Single supply voltage of 200 V

·Internal reference voltage of 2.5 V

·Fixed gain of 50

·Black-Current Stabilization (BCS) circuit

·Thermal protection.

3. Ordering Information

Type

Number

TDA6107Q DBS9MPF

Name Description Version

Plastic DIL-bent-SIL medium power package with fin; 9 leads

2. General Description

The TDA6107Q includes three video output

amplifiers in one plastic DIL-bent-SIL 9-pin

medium power (DBS9MPF) package (SOT

111-1), using high-voltage DMOS technology,

and is intended to drive the three cathodes of a

colour CRT directly. To obtain maximum

performance, the amplifier should be used with

black-current control.

Package

(continued)

SOT 111 - 1

4. Block Diagram

Fig. 19 Block Diagram (One Amplifier Shown)

5. Refer to Table 9 about Functions and Data of the IC’s Each Pin.

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