Toshiba 34HF84 Service Manual

SERVICE MANUAL

DOCUMENT CREATED IN JAPAN, June, 2004

Color Television

34HF84

FILE NO. 020-200406

N4WS Chassis

(TAC0404)

TABLE OF CONTENTS

CHAPTER 1 GENERAL ADJUSTMENTS

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

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

SERVICE MODE ...................................................................................................................................................... 6

ELECTRICAL ADJUSTMENTS ................................................................................................................................ 8

CIRCUIT CHECKS ................................................................................................................................................. 10

CHAPTER 2 SPECIFIC INFORMATIONS

SETTING & ADJUSTING DATA .............................................................................................................................. 11

LOCATION OF CONTROLS ................................................................................................................................... 12

ADDING CHANNELS TO THE TV'S MEMORY ...................................................................................................... 14

CHASSIS AND CABINET REPLACEMENT PARTS LIST ......................................................................................15

PC BOARDS BOTTOM VIEW................................................................................................................................. 24

TERMINAL VIEW OF TRANSISTORS ................................................................................................................... 34

CIRCUIT BLOCK DIAGRAM .................................................................................................................................. 37

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

APPENDIX:

CIRCUIT DIAGRAM

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 hazardous 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 circumstances, exceed (B) kV.

Refer to table-1 for high voltage (A), (B). (See SETTING & ADJUSTING DATA on page 11)

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 reading 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.

SAFETY PRECAUTION

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, following 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 protection, 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 characteristics for X-RAY RADIATION protection. For continued safety, parts replacement should be undertaken only after referring to the PRODUCT SAFETY NOTICE below.

WARNING : Service should not be attempted by anyone unfamiliar with the necessary precautions on this receiver. The following 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 service is performed on the receiver.

2. Always discharge the picture tube anode to the CRT conductive coating before handling the picture tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled. Use shatter proof goggles and keep picture tube away from the unprotected body while handling.

3. When replacing a chassis in the cabinet, always be certain 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:

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

F, 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 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 constitutes a potential shock hazard and must be corrected immediately.

AC VOLTMETER

0.15µF

Good earth ground such as a water pipe, conduit, etc.

1500 ohm 10 watt

F capacitor. Re-

Place this probe on each exposed metallic part.

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 characteristics 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.

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

TION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF SERVICE MANUAL.

SET-UP ADJUSTMENT FOR FLAT TUBE

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

Refer to figure 1.

COLOR PURITY ADUSTMENT

(1)Let the screen face in the installing direction or toward the east (when it is to be moved), bring up the service mode

screen after demagnetizing (front, left, right, and top) with the degaussing coil, receive white signals by pressing the [TV/VIDEO] button, and then the receiver should be operated for more than 40 minutes.

(2)Perform rough adjustment of the central convergence with the P/C magnet according to the adjustment item.

(3)Receive built-in green signals, loosen set screws on the deflection yoke, remove rubber wedges, and shift the deflection

yoke to toward front.

(4)Move alternately the two 2-pole magnets of the P/C magnets so that the green raster can come to the center of the

screen.

Figure 1.

2-pole purity magnet

(27": Magnet is fixed with deflection yoke.)

Green Belt

Sub-4-pole convergence magnet (32" : 34") Sub-4-pole convergence magnet (to be installed on deflection yoke for 30", 32”)

Main 4-pole convergence magnet (30" : 32") 6-pole convergence magnet (34") 6-pole convergence magnet (30" : 32") Main 4-pole convergence magnet (34")

P/C magnet installing position A

• 30"=26.5 mm

• 32"=30.5 mm or 32.5 mm

• 34"=37 mm

• 34"=39 mm

(5)Receive built-in red and blue signals, check that there is no inclination of the single color raster toward one side, and if

each color tilts to a great extent, make adjustment with the 2-pole magnet so that the 3 colors will come to the center evenly.

(6)Receive the green raster, shift the deflection yoke from a

foremost position (hitting against the picture tube) to a

Shift deflection yoke

(7) Perform marking of each point on

(6)

(8)

the tape of picture tube

backward position horizontally, stop the deflection yoke at a position where it begins to become a green raster, and perform accurate marking on the picture tube.

(7)Shift the deflection yoke further backward, and perform

Picture tube

CRT-D board

accurate marking at a position where the green raster begins to being luck.

(8)Fix the deflection yoke at a position 60% forward within

the range marked in items (6) and (7) above.

CONVERGENCE ADJUSTMENTS

100 60 0%

Fix the deflection yoke at a position 60% forward from a point between (6) and (7)

P/C Mag

* Adjust the convergence magnet to get vest convergence in the the order to (1) ~ (5).

■ CENTER CONVERGENCE:

(1)Receive the white crosshatch or dot pattern from the service signal generator.

(2)Use the 2 pieces of main 4-pole magnets of P/C magnets, change the open angle, and align the red and blue vertical

lines on the screen center.

(3)Freeze the open angle of the main 4-pole magnets, turn them simultaneously, and align the horizontal lines.

(4)Take the same steps for items (2) and (3) above and align red/blue with green on the screen center using two 6-pole

magnets.

(5)Adjust the sub-4-pole magnets only in case there is any deviation of Xv bow-shaped convergence. (To be usually set at

the initial position)

Align both sides with the sub-4-pole magnets and minimize the deviation of blue and red with the main 4-pole magnets.

blue

blue red

red

Main 4-pole magnet

red/blue

green

6-pole magnet

■ CIRCUMFERENCE CONVERGENCE:

Perform correction in the following manner.

blue

green

red

(Parts code:23 948 274) TC-S

blue

green

red

S N

Blue color or blue mark

*Insert the correction piece between the picture tube and the deflection yoke.

Bonded surface

(Insertion position of correction piece)

Adjust VR 1 and minimize the deviation of YH. *Only 27", 30" and 32".

Red

green

blue

green

Red

Xv bow-shaped deviation of convergence

blue

green

red

Sub-4-pole magnet

• Adjust coils and minimize deviation (The 27” unit has coils underneath it)

■ 30", 27", 32"

blue

green

red

(Parts code:23 948 464)

N S

Transparent

Bonded surface

Red

green

blue

green

Red

Adjust VR 2 (YHC) and minimize the deviation of YH.

Red

blue

green

blue

Red

blue

Red

green

Red

blue

Adjust VR 3 (YV) and minimize the deviation of YV.

Red

green

blue

green

Red

blue

green

blue

red

green

blue

red

VR3

VR2 VR1

■ 34"

YV YHC

blue

green

Red

green

blue

green

Red

blue

YV YHC

27" (Part No. 23 947 371)

32", 30" (Part No. 23 947 121)

34" (Part No. 23 993 080)

Perform correction by inserting the

correction piece into the clear-

ance of terminal board coils of

the deflection yoke.

Note:

Perform insertion by turning the

metal side to the terminal board

metal side to the terminal board side of the deflection yoke.

SERVICE MODE

1. ENTERING TO SERVICE MODE

1) Press MUTE button twice on Remote Control.

MUTE

2. DISPLAYING THE ADJUSTMENT MENU

1) Press MENU button on TV.

Service mode

3. KEY FUNCTION IN THE SERVICE MODE

The following key entry during display of adjustment menu provides special functions.

2) Press MUTE button again to keep pressing.

Adjustment mode

Press

3) While pressing the MUTE button, press MENU button on TV set.

(Service mode display)

Item

Data

Screen adjustment mode ON/OFF: TV (ANT)/VIDEO button (on TV) Selection of the adjustment items : Channel / (on TV or Remote) Change of the data value : Volume / (on TV or Remote) Adjustment menu mode ON/OFF : MENU button (on TV) Initialization of the memory (QA02) : RECALL+Channel button on TV ( ) Initialization of the self diagnostic data: RECALL+Channel button on TV ( )

“RCUT” selection : 1 button “GCUT” selection : 2 button “BCUT” selection : 3 button “SCNT” selection : 4 button “COLC” selection : 5 button Self diagnostic display : 9 button

4. SELECTING THE ADJUSTING ITEMS

1) Every pressing of CHANNEL button in the service mode changes the adjustment items in the order of table-2. ( button for reverse order)

Refer to table-2 for preset data of adjustment mode. (See SETTING & ADJUSTING DATA on page 11)

5. ADJUSTING THE DATA

1) Pressing of VOLUME or button will change the value of data in the range from 00H to FFH. The variable range

depends on the adjusting item.

6. EXIT FROM SERVICE MODE

1) Pressing POWER button to turn off the TV once.

INITIALIZATION OF MEMORY DATA OF QA02

After replacing QA02, the following initialization is required.

1. Enter the service mode, then select any register item.

2. Press and hold the RECALL button on the Remote, then press the CHANNEL button on the TV. The initialization of QA02 has been complated.

3. Check the picture carefully. If necessary, adjust any adjustment item above. Perform “Programming Channel Memory” on the owner's manual.

CAUTION: Never attempt to initialize the data unless QA02 has been replaced.

7. SELF DIAGNOSTIC FUNCTION

1) Press “9” button on Remote Control during display of adjustment menu in the service mode. The diagnosis will begin to check if interface among IC’s are executed properly.

2) During diagnosis, the following displays are shown.

SELF CHECK NO. 23 * * * * * * POWER : 000 BUS LINE : OK BUS CONT : OK BLOCK : MAIN SUB SET ID : 01 EEP VER : 02 OPT1 : 05 OPT2 : 70 HDMI NO * * * * * * * * ERR CODE :

Part number of microprocessor (QA01)

Operation number of protection circuit (current limiter) . . . . “000” is normal.

BUS line check “OK” ................... Normal

“SCL-GND” or “NG” ........... SCL-GND short circuit

“SDA-GND” or “NG” ........... SDA-GND short circuit

“SCL-SDA” or “NG” ............ SCL-SDA short circuit

BUS line ACK (acknowledge) check

“OK” ..................... Normal

Display of Location Number . . . . NG

(Display example) “QA02 NG”, “H001 NG”, “Q501 NG” etc.

Note: The indication of failure place is only one place though failure places are plural. When

repair of a failure place finishes, the next failure place is indicated. (The order of priority of indication is left side.)

Sync. signal check Green display ..... Normal

Red display ........ NG

MAIN ........ Main sync

SUB .......... Sub sync (when turn on the PIP)

ID code for TV Set Version of "EEP" Data for "OPT" Part number of HDMI microprocessor HDMI error code

ELECTRICAL ADJUSTMENTS

ITEM ADJUSTMENT PROCEDURE

FOCUS VR ADJ

SUB-BRIGHTNESS (BRTC)

WIDTH (WID)

1. Enter the service mode, then select any register item.

2. Press the TV/VIDEO button on the Remote until the black cross-bar pattern appears on the screen.

3. Adjust the FOCUS control (on T461) for well defined scanning lines on the picture screen.

1. Constrict the picture height until the vertical retrace line appears adjusting the item HIT (HEIGHT).

2. Adjust the CONTRAST control to the minimum.

3. Call up the adjustment mode display, then select the item BRTC.

4. Press the VOLUME or button so the belt of vertical retrace line just disappear.

5. Adjust the CONTRAST control for the desired contrast.

6. Perform the HEIGHT adjustment.

1. Call up the adjustment mode display, then select the item WID.

2. Press the VOLUME or button to get the picture so the left and right edges of raster begins to lack.

3. Press the VOLUME or button to advance the data by 7 steps.

Note : Check the horizontal picture position is correct.

Vertical retrace line

ITEM ADJUSTMENT PROCEDURE

E-W PARABOLA (DPC) (PARA)

HORIZONTAL POSITION (HPOS) VERTICAL POSITION (VPOS)

HEIGHT

(HIT)

1. Call up the adjustment mode display, then select the item PARA.

2. Press the TV/VIDEO button on Remote until the cross-hatch pattern appears on the screen.

3. Press the VOLUME s or t button to make vertical lines straight as shown below.

1. Call up the adjustment mode display, then select the item HPOS or VPOS.

2. Press the TV/VIDEO button on Remote until the white cross-bar or black cross-bar pattern appears on the screen.

3. Adjust the HORIZONTAL and VERTICAL position alternately by pressing the VOLUME s or t button for proper picture position.

4. Check the picture with off-air signal.

1. Call up the adjustment mode display, then select the item HIT.

2. Press the VOLUME s or t button to get the picture so the top of raster begins to lack.

3. Press the VOLUME s button to advance the data by 9 steps.

Note : Check the vertical picture position is correct.

WHITE BALANCE (RCUT) (GCUT) (BCUT) (GDRV) (BDRV)

1. Adjust the CONTRAST control to the center, and BRIGHTNESS control to the

maximum.

2. Call up the adjustment mode display, and press the TV/VIDEO button on Remote

until the white and black pattern appears on the screen.

3. Adjust the following items with the CHANNEL s/t and VOLUME s/t buttons.

RCUT

Item :

GCUT

Item :

BCUT

Item :

4. Press the TV/VIDEO button on TV to display a single horizontal line on the screen.

5. Turn the SCREEN control (FBT) fully counterclockwise and gradually rotate clock-

wise until the first horizontal line appears slightly on the screen.

6. Press the TV/VIDEO button to display the normal picture.

7. Adjust the remaining two “?CUT” items (CHANNEL s/t → TV/VIDEO → VOL-

UME s/t in order) to obtain the slightly lighted horizontal line in the same levels of three (red, green, blue) colors. The line should be white if the adjustments are proper.

Data : 40H Data : 40H Data : 40H

Item :

GDRV Data : 40H

Item :

BDRV Data : 40H

Bright area Adjust "GDRV" or "BDRV" to be white.

Dark area Fine adjust "RCUT", "GCUT" or "BCUT" to be black.

CIRCUIT CHECKS

HIGH VOLTAGE CHECK CAUTION: There is no HIGH VOLTAGE ADJUSTMENT on

this chassis. Checking should be done following the steps below.

1. Connect an accurate high voltage meter to the second anode of the picture tube.

2. Turn on the receiver. Set the BRIGHTNESS and CONTRAST controls to minimum (zero beam current).

3. High voltage must be measured below (B) kV.

Refer to table-1 for high voltage (B). (See SETTING & ADJUSTING DATA on page 11)

4. Vary the BRIGHTNESS control to both extremes to be sure

the high voltage does not exceed the limit under any conditions.

FS CIRCUIT CHECK

The Fail Safe (FS) circuit check is indispensable for the final check in servicing. Checking should be done following the steps below.

1. Turn the receiver on and press the RESET button.

2. Temporarily short TP-(R) and TP-(X) with a jumper wire.

Raster and sound will disappear.

3. The receiver must remain in this state even after removing

the jumper wire. This is the evidence that the FS circuit is functioning properly.

4. To obtain a picture again, temporarily turn the receiver off

and allow the FS circuit more than 5 seconds to reset. Then turn the power switch on to produce a normal picture.

Troubleshooting Guide for Fail Safe Circuit

Check that the set returns to normal operation when pin 12 of Z801(or emitter of Q472) is grounded with jumper wire.

YES NO

Check the voltage across Capacitor C471 is approximately

Refer to table –3 for FBT detection voltage

YES

Defective Fail Safe Circuit

(C)

volts.

(C)

(See SETTING & ADJUSTING DATA on page 12)

Faulty power circuit or horizontal circuit.

CHAPTER 2 SPECIFIC INFORMATIONS

SETTING & ADJUSTING DATA

SAFETY INSTRUCTIONS

HIGH VOLTAGE AT ZERO BEAM: MAX HIGH VOLTAGE:

Table-1

SERVICE MODE

ADJUSTING ITEMS AND DATA IN THE SERVICE MODE:

(A)

(B)

34"

30.0 kV

35.0 kV

Item Name of adjustment

RCUT GCUT BCUT GDRV BDRV

BRTC UVTT HIT

CIRCUIT CHECKS

R CUT OFF G CUT OFF B CUT OFF G DRIVE B DRIVE

BRIGHT CENTER TINT CENTTER PICTURE HIT

Preset

40H 40H 40H 40H 40H

80H 46H 2FH

NORMAL

& FULL

Table-2

FBT DETECTION VOLTAGE

Table-3

Item Name of adjustment Preset

LIN WID PARA CNR TRAP HPOS TCNR BTNR

V-LINEARITY PICTURE WIDTH E-W PARABOLA EW M CORRECTION EW TRAPEZIUM H-POSITION EW TOP CORNER EW BOTTOM COR

(C)

20.1 V

12H 3DH 15H 17H 3CH 4CH 10H 10H

NORMAL

& FULL

+ 24 hidden pages