TOSHIBA 36HFX72 - Service Manual Immediate Download

TOSHIBA CORPORATION

1-1, SHIBAURA 1- CHOME, MINATO-KU, TOKYO 105-8001, JAPAN

FILE NO. 020-200206

SERVICE MANUAL

COLOR TELEVISION

N2PS Chassis

36HFX72, 36HF72

PUBLISHED IN JAPAN.

Jun. 2002

(TAC0231)

(TAC0230)

GENERAL

ADJUSTMENTS

SPECIFIC

INFORMATIONS

TABLE OF CONTENTS

CHAPTER 1 GENERAL ADJUSTMENTS

SAFETY INSTRUCTIONS ........................................................................................................................................ 3

SET-UP ADJUSTMENT ............................................................................................................................................ 4

SERVICE MODE ...................................................................................................................................................... 8

ELECTRICAL ADJUSTMENTS .............................................................................................................................. 11

CIRCUIT CHECKS ................................................................................................................................................. 13

CHAPTER 2 SPECIFIC INFORMATIONS

SETTING & ADJUSTING DATA .............................................................................................................................. 14

LOCATION OF CONTROLS ................................................................................................................................... 15

PROGRAMMING CHANNEL MEMORY ................................................................................................................. 17

CHASSIS AND CABINET REPLACEMENT PARTS LIST ......................................................................................18

PC BOARDS BOTTOM VIEW ................................................................................................................................. 33

TERMINAL VIEW OF TRANSISTORS ................................................................................................................... 42

CIRCUIT BLOCK DIAGRAM .................................................................................................................................. 44

SPECIFICATIONS .............................................................................................................................................. END

APPENDIX:

CIRCUIT DIAGRAM

GENERAL

ADJUSTMENTS

SPECIFIC

INFORMATIONS

CHAPTER 1 GENERAL ADJUSTMENTS

SAFETY INSTRUCTIONS

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "X-RAY RADIATION PRECAUTION", "SAFETY PRECAU-

TION" AND "PRODUCT SAFETY NOTICE" INSTRUCTIONS BELOW.

X-RAY RADIATION PRECAUTION

1. Excessive high voltage can produce potentially hazard-

ous X-RAY RADIATION. To avoid such hazards, the high

voltage must not be above the specified limit. The nominal

value of the high voltage of this receiver is (A) kV at zero

beam current (minimum brightness) under a 120V AC

power source. The high voltage must not, under any cir-

cumstances, exceed (B) kV.

Refer to table-1 for high voltage (A), (B).

(See SETTING & ADJUSTING DATA on page 14)

Each time a receiver requires servicing, the high voltage

should be checked following the HIGH VOLTAGE CHECK

procedure in this manual. It is recommended that the read-

ing of the high voltage be recorded as a part of the service

record. It is important to use an accurate and reliable high

voltage meter.

2. This receiver is equipped with a Fail Safe (FS) circuit which

prevents the receiver from producing an excessively high

voltage even if the B+ voltage increases abnormally. Each

time the receiver is serviced, the FS circuit must be checked

to determine that the circuit is properly functioning, follow-

ing the FS CIRCUIT CHECK procedure in this manual.

3. The only source of X-RAY RADIATION in this TV receiver

is the picture tube. For continued X-RAY RADIATION pro-

tection, the replacement tube must be exactly the same

type tube as specified in the parts list.

4. Some part in this receiver have special safety-related char-

acteristics for X-RAY RADIATION protection. For contin-

ued safety, parts replacement should be undertaken only

after referring to the PRODUCT SAFETY NOTICE below.

SAFETY PRECAUTION

Connect a 1500 ohm 10 watt resistor, paralleled by a 0.15

µF, AC type capacitor, between a known good earth ground

(water pipe, conduit, etc.) and the exposed metallic parts,

one at a time. Measure the AC voltage across the combi-

nation of 1500 ohm resistor and 0.15

µF capacitor. Re-

verse the AC plug at the AC outlet and repeat AC voltage

measurements for each exposed metallic part. Voltage

measured must not exceed 0.3 volts rms. This corresponds

to 0.2 milliamp. AC. Any value exceeding this limit consti-

tutes a potential shock hazard and must be corrected im-

mediately.

WARNING : Service should not be attempted by anyone unfa-

miliar with the necessary precautions on this receiver. The fol-

lowing are the necessary precautions to be observed before

servicing this chassis.

1. An isolation Transformer should be connected in the power

line between the receiver and the AC line before any serv-

ice is performed on the receiver.

2. Always discharge the picture tube anode to the CRT con-

ductive coating before handling the picture tube. The pic-

ture tube is highly evacuated and if broken, glass frag-

ments will be violently expelled. Use shatter proof gog-

gles and keep picture tube away from the unprotected body

while handling.

3. When replacing a chassis in the cabinet, always be cer-

tain that all the protective devices are put back in place,

such as; non-metallic control knobs, insulating covers,

shields, isolation resistor-capacitor network etc.

4. Before returning the set to the customer, always perform

an AC leakage current check on the exposed metallic parts

of the cabinet, such as antennas, terminals, screwheads,

metal overlays, control shafts etc. to be sure the set is

safe to operate without danger of electrical shock. Plug

the AC line cord directly into a 120V AC outlet (do not use

a line isolation transformer during this check). Use an AC

voltmeter having 5000 ohms per volt or more sensitivity in

the following manner:

AC VOLTMETER

0.15

µF

Good earth ground

such as a water

pipe, conduit, etc.

Place this probe on

each exposed

metallic part.

1500 ohm

10 watt

PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in this chassis have special safety-related characteristics. These characteristics are

often passed unnoticed by a visual inspection and the protection afforded by them cannot necessarily be obtained by using

replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety charac-

teristics are identified in this manual and its supplements; electrical components having such features are identified by the

international hazard symbols on the schematic diagram and the parts list.

Before replacing any of these components, read the parts list in this manual carefully. The use of substitute replacement

parts which do not have the same safety characteristics as specified in the parts list may create shock, fire, X-ray radiation

or other hazards.

GENERAL

ADJUSTMENTS

SPECIFIC

INFORMATIONS

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "X-RAY RADIATION PRECAUTION", "SAFETY PRECAU-

TION" AND "PRODUCT SAFETY NOTICE" ON PAGE 3 OF THIS MANUAL.

SET-UP ADJUSTMENT

s The following adjustments should be made when a complete realignment is required or a new picture tube is installed.

Perform the adjustments in order as follows :

1. Color Purity

2. Convergence

3. White Balance

Note: 1. The PURITY/CONVERGENCE MAGNET assembly and rubber wedges need mechanical positioning.

Refer to figure 1.

2. Mounting position of the purity magnet assembly should fit to same position as old one because slightly difference

to the position depend on a kind of tube.

* There are no adjustment of purity and convergence in some picture tube (Unified with purity magnet)

COLOR PURITY ADJUSTMENT

NOTE : Before attempting any purity adjustments, the

receiver should be operated for at least fifteen

minutes.

1. Evenly degauss the entire screen.

2. Set the CONTRAST and BRIGHTNESS Controls to

the maximum.

3. Display built-in green raster using the TEST SIGNAL

SELECTION function.

4. Loosen the clamp screw holding the deflection yoke

(and remove the rubber Wedges).

5. Slide the yoke forward or backward to provide vertical

green belt (zone) in the picture screen.

6. Rotate and spread the tabs of the purity magnet (See

figure 4.) around the neck of the picture tube until the

green belt is in the center of the screen. At the same

time, center the raster vertically by adjusting the mag-

net as shown below.

7. Move the yoke slowly forward or backward until a uni-

form green screen is obtained.Tighten the clamp screw

of the yoke temporarily.

8. Check the purity of the red and blue raster.

9. Put four wedges into the space between the picture

tube and the yoke to hold the yoke in the adjusted

position. (See figure 2.)

Do not tilt the yoke by excessive insertion of the wedge.

10. Remove cover paper of wedge and stick wedges on

the tube to fix the yoke in the adjusted position.

Fix the wedges with glass cloth tapes.

Green Belt

DEFLECTION YOKE

1-5/8"

PURITY/

CONV.

MAGNET

Xv Coil

Adhesive

RUBBER WEDGES

DEFLECTION

YOKE

Figure 2.

Figure 1.

GENERAL

ADJUSTMENTS

SPECIFIC

INFORMATIONS

CONVERGENCE ADJUSTMENTS

NOTE: Before attempting any convergence adjustments,

the receiver should be operated for at least fifteen

minutes.

CENTER CONVERGENCE ADJUSTMENT

1. Display built-in cross-dot pattern using the TEST SIG-

NAL SELECTION function.

2. Adjust the BRIGHTNESS and CONTRAST Controls

for well defined pattern.

3. Loosen the tightening ring and adjust two tabs of the

4-Pole Magnets to change the angle between them

(See figure 4.) and superimpose red and blue vertical

lines in the center area of the picture screen.

(See figure 3.)

4. Turn the both tabs at the same time keeping the con-

stant angle to superimpose red and blue horizontal

lines at the centre of the screen. (See figure 3.)

5. Adjust two tabs of 6-Pole Magnets to superimpose red/

blue line with green one. Adjusting the angle affects

the vertical lines and rotating both magnets affects the

horizontal lines.

6. Repeat adjustments 3, 4, 5 keeping in mind red, green

and blue movement, because 4-Pole Magnets and 6-

Pole magnets interact and make dot movement com-

plex.

7. After completing the "CENTER CONVERGENCE AD-

JUSTMENT" tighten the tightening ring to fix the mag-

nets.

Figure 3.

Xv COIL ADJUSTMENT

Adjust the Xv coil (on the deflection yoke) to correct

misconvergence at both sides on screen.

Use a hexagonal tip stick (plastic) to adjust the core of

coil.

BLU

BLU RED

RED

6-POLE MAGNETS

MOVEMENT

4-POLE MAGNETS

MOVEMENT

RED/BLUE

RED/BLUE GRN

GRN

Center Convergence by Convergence Magnets

Clockwise Adjustment Counterclockwise Adjustment

Xv Cross Pattern View

SCREEN-CORNER CONVERGENCE

When the misconvergence is still evident on corners even

though the above adjustment is done, use the ferrite sheet

(Part No. 23993622) to correct misconvergence.

1. Put ferrite sheets into the space under the yoke.

Decide such position that misconvergence becomes

minimum, watching picture screen. (See figure below.)

2. Remove cover paper of ferrite sheet to stick it in the

place on the tube. Put adhesive tapes on ferrite sheets

to fix.

Figure 4.

Ferrite

Sheets

Ferrite

Sheets

For correcting misconvergence

on the position A

4-POLE

MAGNETS

6-POLE

MAGNETS

PURITY

MAGNETS

PURITY/CONVERGENCE

MAGNETS

ADJUST THE ANGLE

(VERTICAL LINES)

FIXED

ROTATE TWO TABS

AT THE SAME TIME

(HORIZONTAL LINES)

ADJUSTMENT OF MAGNETS

Clockwise Adjustment

Counterclockwise Adjustment

XV Cross Pattern View