Haier 21FA18-T Schematic

Order NO.WH070625S001V0

21FA18-T

(TB8873)

violation of law.

WARNING

This service information is designed for experienced repair technicians only and is not designed for use by the general public. It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product. Products powered b electricity should be serviced or repaired only by experienced professional technicians. Any attempt to service or repair the product deal with in this service information by anyone else could result in serious injury or death.

CONTENT

1. SPECIFICATIONS………………………………………………………………………….. 3

2. WARNING…………………………………………………………………………………….. 4

3. FEATURES AND TECHINICAL DESCRIPTION………………………………………... 11

4. ADJUSTMENT………………………………………………………………………..………1 1

5. CIRCUIT DIAGRAM…………………………………………………………………………18

6. WIRING CONNECTION DIAGRAM……………………………………………………….18

7. CIRCUIT EXPLANATION.…………………………..…………………..………………….19

8. MAINTENANCE SERVICE AND TROUBLE SHOOTING………………………………22

1. Specification

MODEL

ITEM

NO.

PICTURE

1 2 3

5 6 7

AUDIO

9 10 11 12 13 14 15 16 17

JACK

18 19 20 21 22 23

FUNCTION

Main IC 8873

CRT

Color system

Audio system

O.of channels

OSD language

Multi-picture modes

AV stereo

Super woofer

Surrounding sound

Treble/bass boost

Left/right balancer

ICAM

Multi-audio modes

Tone adjuster

MTS/SAP

Auto-volume leveling

AV input

AV output

DVD terminal

S-video jack

Headphone socket

SCART socket

21FA18-T

PURE FLAT 25

ENGLISH 29

back 1,side1 41

NO.

PAL 26

BG 27

218 28

5 30

√ × × × √ × √ × × ×

back 1 42

back 1 43

back 1 44

× ×

ITEM

SOFTWARE

PARAMETER

FUNCTION

Digital curtain

Slow fading on & off

Semitransparent menu

on-flshing channel

changing

ZOOM

16:9 mode

Games

Calendar

Child-lock

Multi-functional lock

o-picture listening

Background light

Auto-timer on

FM RADIO

V-CH IP

O. of built-in speakers

Audio output power(W)

Total power input（W） Voltage range（V） Power frequency（Hz）

Time of sleep timer(MINS)

et weight(KG)

Gross weight(KG)

et dimension(MM)

Packaged dimension(MM)

21FA18-T

615/482/452 651/576/526

MODEL

√ √ √

√

√ √

√ √ √ √ × √ × ×

5×2

160~250

50/60

120

23 26

2. Warning

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 plug from AC outlet. Don't clean the cabinet and the screen with benzen e, petrol a nd other chemical s.

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 sh ock, don't make the TV set rain or moistu re.

5. Don't ope n the back cover , otherwise it is possib le to dama ge the c ompon ents in the TV set and ha rm you.

Don' t place the TV set in the sunshine or near heat source .

6. When the TV set i s n't going t o be used for long time or it is in thunder and lightening, please pull out the plug from AC outlet a nd the ante nna plug from th e 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 cleane d w it h a dry cotton cloth after cutting off the power.D on't use any cleanser. If using ha r d clot h, the tube surf ace will be dam a ged.

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

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 spray 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 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 st atic electricity sufficient to damage an ES device.)

General Soldering Guidelines

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.

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

lead. Keep the soldering iron tip clean and well tinned. 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. 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. CAUTION: Work quickly to avoid overheating the circuit board printed foil.

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 Transistor 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. Remove the heat sink mounting screw (if so equipped). Carefully remove the transistor from the heat sink of the circuit board. Insert new transistor in the circuit board. Solder each transistor lead, and clip off excess lead. Replace heat sink.

Diode Removal/Replacement

Remove defective diode by clipping its leads as close as possible to diode body. Bend the two remaining leads perpendicularly to the circuit board. Observing diode polarity, wrap each lead of the new diode round the corresponding lead

on the circuit board. Securely crimp each connection and solder it. Inspect (on the circuit board copper side) the solder joints of the two “original” leads. If they

are not shiny, reheat them and if necessary, apply additional solder.

Fuse and Conventional Resistor Removal/Replacement

1. Clip each fuse or resistor lead at top of the circuit board hollow stake.

2. Securely crimp the leads of replacement component around notch at stake top.

3. Solder the connections

CAUTION: Maintain original spacing between the replaced component and adjacent

components and the circuit board to prevent excessive component temperatures.

Circuit Board Foil Repair

Excessive heat applied to the copper foil of any printed circuit board will weaken the adhesive that bonds foil to the circuit board causing the foil to separate from or “lift-off” the board. The following guidelines and procedures should be followed whenever this condition is encountered.

At IC Connections

To repair a defective copper pattern at IC connections use the following procedure to install a jumper wire on the copper pattern side of the circuit board. (Use this technique only on IC connections).

1. Carefully remove the damaged copper pattern with a sharp knife. (Remove only as

much copper as absolutely necessary).

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