Haier HTX21S31 Schematic

X21S31

COLOR TELEVISION

Service Manual

MODEL: HTX21S31

Haier

Features



 PAL M/N, NTSC M

 Front Audio/Video input  V-CHIP, CCD  181 Channel

Haier Group

NO:M-LA-EC-2199-76812 -Edition: 2002.12.30

CONTENTS

1 Contents--------------------------------------------------------------------1

2 Product Code illumination and Series Introduction--------------------2 3 Features--------------------------------------------------------------------------------3 4 Safety Precautions------------------------------------------------------------------4 5 Warning and Cautions-------------------------------------------------------------5 6 Net dimension----------------------------------------------------------------------11 7 Parts and Functions--------------------------------------------------------------12 8 Remote Controller Functions--------------------------------------------------13 9 Program Diagram------------------------------------------------------------------14 10 Maintenance Service and Trouble shooting------------------------------15 11 Circuit Diagram---------------------------------------------------------------------18 12 Circuit Explanation----------------------------------------------------------------22 13 Adjustment---------------------------------------------------------------------------24 14 Exploded View----------------------------------------------------------------------27 15 List of Parts--------------------------------------------------------------------------28

Damageable Parts List-----------------------------------------------------------41

Information of Resistors and Capacitors----------------------------------41

Product Code illumination and Series Introduction

T X 21 S31

Color television appearance

CRT size (unit: inch)

Toshiba

Haier

Features

PICTURE

AUDIO

ITEM

JACK

NO.

FUNCTION

Main IC 76814

CRT

Color system

Audio system

Number of channels

OSD language

Multi-picture modes

AV stereo

Super woofer

Surrounding sound

Treble/bass boost

Left/right balancer

NICAM

Multi-audio modes

Tone adjuster

MTS/SAP

Auto-volume leveling

AV input

AV output

DVD terminal

S-video jack

Headphone socket

SCART socket

Flat square 25

MODEL

HTX21S31

NTSC 26

M 27

181 28

F S P

Front 1 41

NO.

ITEM

SOFTWARE

PARAMETER

FUNCTION

Digital curtain

Slow fading on & off

Semitransparent menu

Non-flashing channel changing

ZOOM

16:9 mode

Games

Calendar

Child-lock

Multi-functional lock

No-picture listening

Background light

Auto-timer on

CCD

V-CHIP

Number of built-in speakers

Audio output power (W)

Total power input W

Voltage range

Power frequency

Time of sleep timer (MINS)

Net weight (KG)

Gross weight (KG)

Net dimension (MM)

Packaged dimension (MM)

Quantity for 20' container

Quantity for 40' container

Quantity for 40' high container

MODEL

HTX21S31

90VAC-250V

120

23.5

610X475X46

685X545X52

Safety Precautions

SAFETY PRECAUTIONS

IMPORTANT SAFETY NOTICE

Many electrical identify these parts and mechanical parts in this chassis have special safety-related

characteristics! In the Schematic Diagram and Replacement Parts List.

It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards.

Do not modify the original design without permission of the manufacturer.

General Guidance

An Isolation Transformer should always be used during the servicing of a receiver whose chassis is not isolated from the AC power line. Use a transformer of adequate power rating as this protects the technician from accidents that might result in personal injury caused by electrical shocks.

It will also protect the receiver and it’s components from being damaged by accidental shorts of the circuitry that might be inadvertently introduced during the service operation.

If any fuse (or Fusible Resistor) in this TV receiver is blown, replace it with a specified one.

When replacing a high wattage resistor (Oxide Metal Film Resistor, over 1W), keep the resistor 10mm away from PCB.

Keep wires away from high voltage or high temperature parts.

Due to the high vacuum and large surface area of the picture tube, extreme care should be taken in handling the Picture Tube. Do not lift the Picture Tube by its Neck.

X-RAY Radiation

Warning:

The source of X-RAY RADIATION in this TV receiver is the High Voltage Section and the Picture Tube.

For continued X-RAY RADIATION protection, the replacement tube must be of the same type as specified in the Replacement Parts List.

Before returning the receiver to the customer,

Always perform an AC leakage current check on the exposed metallic parts of the cabinet, such as antennas, terminals, etc., to make sure that the set is safe to operate without any danger of electrical shock.

Warning and Cautions

1. When you clean the TV set, please pull out the power plu clean the cabinet and the screen with benzene, petrol and other chemicals.

from AC outlet. Don't

In order to prolong the using life of the TV set, please place it on a ventilated place.

4. To prevent the TV set from firing and electric shock, don't make the TV set rain or moisture.

5. Don't open the back cover, otherwise it is possible to damage the components in the TV set and harm you.

Don't place the

TV set in the sunshine or near heat source.

6. When the TV set isn't going to be used for long time or it is in thunder and lightening, please pull out the pl ug from AC outlet and the antenna plug from the cover of the TV set.

Explanation on the display tube

Generally, it is not needed to clean the tube surface. However, if necessary,its surface can be cleaned with a dry cotton cloth after cutting off the power.Don't use any cleanser. If using hard cloth, the tube surface will be damaged.

CAUTION: Before servicing receivers covered by this service manual and its supplements and addenda, read and follow the SAFETY PRECAUTIONS.

Warning and Cautions

NOTE: If unforeseen circumstances create conflict between the following servicing precautions and any of the safety precautions, always follow the safety precautions. Remember: Safety First.

General Servicing Precautions

1). Always unplug the receiver AC power cord from the AC power source before:

a. Removing or reinstalling any component, circuit board module or any other assembly of the

receiver.

b. Disconnecting or reconnecting any receiver electrical plug or other electrical connection.

c. Connecting a test substitute in parallel with an electrolytic capacitor in the receiver.

CAUTION: A wrong substitution part or incorrect installation polarity of electrolytic capacitors

may result in an explosion hazard.

d. Discharging the picture tube anode.

2). Test high voltage only by measuring it with an appropriate high voltage meter or other voltage-measuring device (DVM, FETVOM, etc.) equipped with a suitable high voltage probe. Do not test high voltage by “drawing an arc”.

3) .Discharge the picture tube anode only by (a) first connecting one end of an insulated clip lead to the degaussing or kine aquadag grounding system shield at the point where the picture tube socket ground lead is connected, and then (b) touch the other end of the insulated clip lead to the picture tube anode button, using an insulating handle to avoid personal contact with high voltage.

4) .Do not sprays chemicals on or near this receiver or any of its assemblies.

5). Unless specified otherwise in this service manual, clean electrical contacts only by applying the following mixture to the contacts with a pipe cleaner, cotton-tipped stick or comparable nonabrasive applicator; 10% (by volume) Acetone and 90% (by volume) isopropyl alcohol (90%-99% strength)

CAUTION: This is a flammable mixture.

Unless specified otherwise in this service manual, lubrication of contacts is not required.

6). Do not defeat any plug / socket B+ voltage interlocks with which receivers covered by this service manual might be equipped.

7). Do not apply AC power to this instrument and/or any of its electrical assemblies unless all

solid-state device heat sinks are correctly installed.

8) Always connect the test receiver ground lead to the receiver chassis ground before connecting

the test receiver positive lead.

Always remove the test receiver ground lead last.

9). Use with this receiver only the test fixtures specified in this service manual.

CAUTION: Do not connect the test fixture ground strap to any heat sink in this receiver.

Electrostatic ally Sensitive (ES) Devices

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such

Warning and Cautions

components are usually called Electrostatic ally Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field effect transistors and semiconductor “chip” components. The following techniques should be used to help reduce the incidence of component damage caused by static electricity.

1) Immediately before handling any semiconductor component or semiconductor- equipped

assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging wrist strap device, which should be removed to prevent potential shock prior to applying power to the unit under test.

2) After removing an electrical assembly equipped with ES devices, place the assembly on a

conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.

3) Use only a grounded-tip soldering iron to solder or unsolder ES devices.

4) Use only an anti-static type folder removal device. Some solder removal devices not classified as

“anti-static” can generate electrical charges sufficient to damage ES devices.

5) Do not use freon-propelled chemicals. These can generate electrical charges sufficient to

damage ES devices.

6) Do not remove a replacement ES device from its protective package until immediately before you

are ready to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive material).

7) Immediately before removing the protective material from the leads of a replacement ES device,

touch the protective material to the chassis or circuit assembly into which the device will be installed.

CAUTION: Be sure no power is applied to the chassis or circuit, and observe all other safety

precautions.

8) Minimize bodily motions when handling unpackaged replacement ES devices. (Otherwise even

some normally harmless motions such as mutual brushing of your clothes’ fabric or lifting of your foot from a carpeted floor might generate static electricity sufficient to damage an ES device.)

General Soldering Guidelines

1) Use a grounded-tip, low-wattage soldering iron and appropriate tip size and shape that will

maintain tip temperature within the range of 500 oF to 600 oF.

2) Use an appropriate gauge of RMA resin-core solder composed of 60 parts tin/40 parts lead.

3) Keep the soldering iron tip clean and well tinned.

4) Thoroughly clean the surfaces to be soldered. Use a mall wire bristle (0.5 inch, or 1.25cm) brush

with a metal handle. Do not use freon-propelled spay-on cleaners.

5) Use the following unsoldering technique

a. Allow the soldering iron tip to reach normal temperature. (500 o F to 600o F)

b. Heating the component lead until the solder melts.

c. Quickly draw the melted solder with an anti-static, suction-type solder removal device with

solder braid.

Warning and Cautions

CAUTION: Work quickly to avoid overheating the circuit board printed foil.

1) Use the following unsoldering technique

a. Allow the soldering iron tip to reach normal temperature. (500 o F to 600o F)

b. First, hold the soldering iron tip and solder the strand against the component lead until the

solder melts.

c. Quickly move the soldering iron tip to the junction of the component lead and the printed

circuit foil, and hold it there only until the solder flows onto and around both the component lead and the foil.

CAUTION: Work quickly to avoid overheating the circuit board printed foil.

d. Closely inspect the solder area and remove any excess or splashed solder with a small

wire-bristle brush.

Remove /Replacement

Some chassis circuit boards have slotted holes (oblong) through which the IC leads are inserted and then bent flat against the circuit foil. When holes are of slotted type, the following technique should be used to remove and replace the IC. When working with boards using the familiar round hole, use the standard technique as outlined.

Removal

Desolder and straighten each IC lead in one operation by gently prying up on the lead with the soldering iron tip as the solder melts.

Draw away the melted solder with an anti-static suction-type solder removal device (or with solder braid) before removing the IC.

Replacement

Carefully insert the replacement IC in the circuit board.

Carefully bend each IC lead against the circuit foil pad and solder it.

Clean the soldered areas with a small wire-bristle brush. (It is not necessary to reapply acrylic coating to the areas).

“Small-Signal” Discrete Tr ansistor Removal/Replacement

Remove the defective transistor by clipping its leads as close as possible to the component body.

Bend into a “U” shape the end of each of three leads remaining on the circuit board.

Bend into a “U” shape the replacement transistor leads.

Connect the replacement transistor leads to the corresponding leads extending from the circuit board and crimp the “U” with long nose pliers to insure metal to metal contact then solder each connection.

Power Output, Transistor Device Removal/Replacement

Heat and remove all solder from around the transistor leads.

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