Panasonic TX-21JT2C Service Manual

ORDER No. SM-03006

Colour Television

TX-21JT2C Z-M3L Chassis

SPECIFICATIONS

Power Source: 220-240V a.c., 50Hz

Power Consumption: 60W

Stand-by Power Consumption: 1W

Aerial Impedance: 75Ω unbalanced, Coaxial Type

Receiving System: PAL-B/G, PAL-525/60

M.NTSC NTSC (AV only)

Receiving Channels:

VHF E2-E12 VHF H1-H2 (ITALY) VHF A-H (ITALY) VHF R1-R2 VHF R3-R5 VHF R6-R12 UHF E21-E68 CATV (S01-S05) CATV S1-S10 (M1-M10) CATV S11-S20 (U1-U10) CATV S21-S41 (HYPERBAND)

Intermediate Frequency: Video/Audio

Video 38.9MHz, 34MHz Audio 32.9MHz, 33.16MHz, 33.4MHz Colour 34.47MHz (PAL)

34.5MHz, 34.65MHz (SECAM)

Video/Audio Terminals:

AV1 IN Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500mV rms 10kΩ

RGB (21 pin)

Audio (RCAx1) 500mV rms 10kΩ Video (RCAx1) 1V p-p 75Ω

AV1 OUT Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500mV rms 1kΩ

High Voltage: 29kV ± 1kV

Picture Tube: A51QAE320X47P 51cm

Audio Output: 3W (Music Power)

8Ω Impedance

Headphones: 8Ω Impedance

3.5mm

Accessories supplied : Remote Control

2 x R6 (UM3) Batteries

Dimensions:

Height: 482mm Width: 506mm Depth: 484mm

Net weight: 20kg

Specifications are subject to change without notice. Weights and dimensions shown are approximate.

CONTENTS

SAFETY PRECAUTIONS ......................................................................................................................................................... 2

SERVICE HINTS....................................................................................................................................................................... 3

ALIGNMENT SETTINGS .......................................................................................................................................................... 4

WAVEFORM PATTERN TABLE............................................................................................................................................... 5

BLOCK DIAGRAMS.................................................................................................................................................................. 6

PARTS LOCATION................................................................................................................................................................... 7

REPLACEMENT PARTS LIST.................................................................................................................................................. 8

SCHEMATIC DIAGRAMS....................................................................................................................................................... 12

CONDUCTOR VIEWS ............................................................................................................................................................ 17

SAFETY PRECAUTIONS

GENERAL GUIDE LINES

1. It is advisable to insert an isolation transformer in the a.c. supply before servicing a hot chassis.

2. When servicing, observe the original lead dress in the high voltage circuits. If a short circuit is found, replace all parts that have been overheated or damaged by the short circuit.

3. After servicing, see that all the protective devices such as insulation barriers, insulation papers, shields and isolation R-C combinations are correctly installed.

4. When the receiver is not being used for a long period of time, unplug the power cord from the a.c. outlet.

5. Potentials as high as 30kV are present when this receiver is in operation. Operation of the receiver without the rear cover involves the danger of a shock hazard from the receiver power supply. Servicing should not be attempted by anyone who is not familiar with the precautions necessary when working on high voltage equipment. Always discharge the anode of the tube.

6. After servicing make the following leakage current checks to prevent the customer from being exposed to shock hazard.

LEAKAGE CURRENT COLD CHECK

1. Unplug the a.c. cord and connect a jumper between the two prongs of the plug.

2. Turn on the receiver’s power switch.

3. Measure the resistance value with an ohmmeter, between the jumpered a.c. plug and each exposed metallic cabinet part on the receiver, such as screw heads, aerials, connectors, control shafts etc. When the exposed metallic part has a return path to the chassis, the reading should be between 4M ohm and 20M ohm. When the exposed metal does not have a return path to the chassis, the reading must be infinite.

LEAKAGE CURRENT HOT CHECK

1. Plug the a.c. cord directly into the a.c. outlet. Do not use an isolation transformer for this check.

2. Connect a 2kΩ 10W resistor in series with an

exposed metallic part on the receiver and an earth, such as a water pipe.

3. Use an a.c. voltmeter with high impedance to measure the potential across the resistor.

4. Check each exposed metallic part and check the voltage at each point.

5. Reverse the a.c. plug at the outlet and repeat each of the above measurements.

6. The potential at any point should not exceed 1,4Vrms. In case a measurement is outside the limits specified, there is a possibility of a shock hazard, and the receiver should be repaired and rechecked before it is returned to the customer.

HOT CHECK CIRCUIT

a.c. VOLTMETER

ΩΩΩΩ

10 Watts

TO INSTRUMENT'S EXPOSED METALLIC PARTS

Fig. 1.

X-RADIATION WARNING

1. The potential sources of X-Radiation in TV sets are the high voltage section and the picture tube.

2. When using a picture tube test jig for service, ensure that the jig is capable of handling 30kV without causing X-Radiation.

NOTE: It is important to use an accurate periodically calibrated high voltage meter.

1. Set the brightness to minimum.

2. Measure the high voltage. The meter should indicate. 29kV ± 1kV. If the meter indication is out of tolerance, immediate service and correction is required to prevent the possibility of premature component failure.

3. To prevent any X-Radiation possibility, it is essential to use the specified tube.

WATER PIPE

(

EARTH)

SERVICE HINTS

How to remove the rear cover

1. Remove the 5 screws as shown in Fig.2.

SCREWS

LOCATION OF CONTROLS

SCREWS

Fig. 2.

AV Board

Main Board

CRT Board

Focus

Screen

ALIGNMENT PROCEDURE AND OPTION SETTING

Entering SERVICE mode

Service mode is entered by selecting the “mute” remote key and local “down” simultaneously with the sharpness DAC set to Minimum and programme position 99 selected. Service mode 2 is selected by pressing the Recall remote key while in service mode 1.

Service mode navigation

- Up /Down remote keys :cycle through the service items available.

- -/+ remote keys :Decrement/Increment the values within range.

- TV/AV :Store the current data.

- 0 – 7 digit keys :Toggle bits 0-7 in option byte (service mode 2).

Order

3 Vertical Shift 0-63

4 Vertical amplitude 0-63

5 Horizontal shift 0-63

6 Red Cut 0-63

7 Green Cut 0-63

8 Red Drive 0-63

9 Green Drive 0-63

Item

Cut off (VG2)

Vertical slope

LED ON , LED OFF

Range

0-63

10 Blue Drive 0-63

11 AGC 0-63

12 Sub-Colour 0-63

13 Sub-Brightness 0-63

Sub-Colour: Set sub-colour to 16. Sub-Brightness: Set sub-colour to 33. G2 alignment: Before entering into service mode, recall the nominal picture setting :remote key “N”.

From this setting, increase brightness by 11 steps and reduce sharpness to minimum. Tune a colour bar signal on Prg 99 and enter into SVC mode. In SVC mode , select “G2” item and press – or + remote key to control software disable vertical deflection. The user must then adjust G2 voltage on FBT, to find the point where LED is ON. Press – or + remote key to return to normal SVC mode.

White balance: - Select a dark picture and adjust Red Cut and Green Cut to the desired colour temperature.

- Select a bright picture, set Blue Drive to 32 and adjust Red Drive, and Green Drive to the desired colour temperature.

FB401

P.CON+25V

180V

AC220-240V

50Hz

CRT

V801

PELAY

RY501

D501~D504

TV/AV

BLOCK DIAGRAM

TU001

BPL AGC

SDA SCL

BUFFER

Q602

V.OUTPUT IC

IC401 TDA8357J

DOWN

STR

FUNCTION

KEY_IN

IF2

IF1

SDA3SCL

MICON/CHROMA IC

IC101 TDA9360

P.CON+5V

OUTA

INA

22 V+

RF_AGC

INB

V-

LED1

H.OUTPUT

Q401

H.DRIVE

Q405

H_OUT

3.3V(A)

VDD

J801

Vddp

VOC(3)

VI(1)

VIDEO AMP IC

IC801 TDA6107Q

B_OUT

X_TAL

VOC(2)

VOC(1)

VI(2)

VI(3)

213

525351

G_OUT

R_OUT

180V

6VDD

CVBS/Yin

X_TAL

Vp1

R_IN

VCC 14

474648

G_IN

B_IN

AM-OUT 44

T502

D529, D532

D533, D534

EXT.A.IN

AUDIO_OUT

AT3.5V

AT+5.6V

BUFFER

Q601

J701

J1001

HEADPHONE_JACK

T501

8V REG. IC

IC502 KIA7808API

SOUND+B

11715

342

5V REG. IC

IC501 KIA7805API

P.CON+8V

J702

FRONT VIDEO

P.CON+5V

J703

FRONT AUDIO

SPEAKER

SP351

SDA5SCL

EEPROM IC

IC199

S-24C16AFJA-TB-01

D101

AT3.5V

OS101

X101

12MHz

P.CON+8V

SOUND+B

1 2

SOUND AMP IC

IC1001

AN7523

E-1 E-2

PARTS LOCATION

NOTE:

The numbers on the exploded view below refer to the mechanical section of the Replacement Parts List. This diagram is used for representative purposes only.

+ 11 hidden pages