Panasonic TX-28CK2P Schematic

ORDER No. SM-04020

Service Manual

Colour Television

Z-M3P Chassis

TX-28CK2P

SPECIFICATIONS

Power Source: 220 - 240V A.C., 50Hz Video/Audio Terminals:

Power Consumption: 78W AV1 IN Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500mV rms 10KΩ

Stand-by Power Consumption: 1W RGB (21 pin)

Audio (RCA x 2) 500mV rms 10KΩ Video (RCA x 1) 1V p-p 75Ω

Receiving System: PAL B/G, D/K, 525/60

SECAM B/G, D/K AV1 OUT Video (21 pin) M.NTSC Audio (21 pin) 500mV rms 10KΩ NTSC (AV only)

Receiving Channels: VHF E2-E12 Picture Tube: A66QEW13X38 66cm

UHF E21-E68 CATV S1-S10 (M1-M10) High Voltage: 29 ± 1kV CATV S11-S20 (U1-U10) CATV S21-S41 (HYPERBAND) Audio Output: 20W

(Music Power) 8Ω

Headphones: 8Ω

Intermediate Frequency: Video 38.9MHz, 34MHz 3.5mm Video/Audio

Audio 32.9MHz, 33.16MHz, 33.4MHz Accessories: Remote Control

40.4MHz, 32.4MHz (A2 STEREO) 2 x R6 (UM3) Batteries

33.05MHz, 34.05MHz (NICAM)

Impedance

1V p-p 75Ω

Colour 34.47MHz (PAL) Dimensions:

34.5MHz, 34.65MHz (SECAM) Height: 571.5mm Width: 650.0mm Depth: 500.5mm

Net Weight: 31kg

NOTE:

Specifications are subject to change witho ut notic e. Weights and dimensions shown are approx imate .

CONTENTS

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

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

ALIGNMENT PROCEDURE.....................................................................................................................................................4

WAVEFORMS...........................................................................................................................................................................5

BLOCK DIAGRAM....................................................................................................................................................................7

PARTS LOCATION...................................................................................................................................................................8

REPLACEMENT PARTS LIST..................................................................................................................................................9

SCHEMATIC DIAGRAMS.......................................................................................................................................................15

PCB CONDUCTOR VIEWS....................................................................................................................................................23

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 7 screws as shown in Fig.2.

SCREWS

Fig. 2.

LOCATION OF CONTROLS

CRT Board

Main Board

Filter Board

Focus Screen

ALIGNMENT PROCEDURE AND OPTION SETTING

Self Check Mode

To enter self check mode, set the programme position to Channel 99. Set sharpness to a minimum, press the status button ( ) on the remote contol whilst simultaneously pressing the down button ( ) at the front of the set. This should bring the set into self check mode.

Entering SERVICE mode

Whilst in self check mode, press the mute remote key ( ) and local down button on the set ( ) simultaneously. The user must make sure that Sharpness is set to a minimum and that the programme position is set to Channel 99 as well. This should bring the user to service mode1. Scroll through the service items using the cursor up and down keys and adjust accordingly using the - /+ keys on the r emote.

Service mode navigation

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

-/+ remote keys :Decrement/Increment the values within range. TV/AV :Store the current data.

ORDER FUNCTIONS AND SETTINGS VALUES (NOMINAL VALUES)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Cut Off Alignment UG2 Vertical Slope V-Slo Vertical Positio n V-Pos Vertical Amplitud e V-Amp Horizontal Position H-Ctr Horizontal Parabola H-Par Horizontal Bow H-Bow Red Colour Cut R-Cut Green Colour Cut G-Cut Red Colour Drive R-Drv Green Colour Drive G-Drv Blue Colour Drive B-Drv RF Automatic Gain Control AGC Sub Colour S-Col Sub Brightness S-Bri East/West Width (Horizontal Amplitude) EW-WD East/West Parabola EW-PR East/West Upper Corner EW-UC East/West Lower Corner EW-LC East/West Trapezium EW-TP

TEST 033 005 045 039 030 021 037 031 063 048 038 035 011 040 017 039 044 042 034

Cut Off UG2 alignment: Adjust it on AV mode.

Set condition is in AV mode without signal. Place the set into an Ageing Test for more than 15 minutes. Adjust the unit to the following settings. R-Cut=32, G-Cut=32, R-Drv=42, G-Drv=42, B-Drv=42. Press the G2 button on the service remote. Adjust the Screen Volum e on the FBT until the indicator on the set will be lit.

White Balance: Adjust this after performing CUT OFF UG2 alignment.

Place the set into an ageing test for approximately 15 minutes. Generate a gray scale pattern from a Pattern Generator. Set the colour balance to normal position. Press the FACTORY button on the service remote. Adjust accordingly using +/- button on the service remote to whiten the settings of R-Cut, G-Cut, R-Drv and G-Drv at each section equally.B-Drv step number however should be fixed at 42.

MICON/CHROMA

WAVEFORMS

20µs

1.00V

20µs

1.00V

20µs

1.00V

20µs

1.00V

5ms

0.5V

6 17

20µs

1.00V

20µs

2.00V

5ms

10.0V

20µs

5.0V

20µs

1.00V

20µs

1.00V

20µs

2.00V

DEFLECTION/CRT

5ms

0.5V

20µs

0.5V

20µs 50V

The following waveforms were measured at the point of the corresponding

NOTE:

balloon number in the schematic diagram.

H-1

WAVEFORMS

20µs 50V

SOUND AMP

2ms

0.50V

0.2ms

5.0V

STEREO

0.2ms

0.50V

0.2ms

0.50V

0.2ms 200mV

2ms

0.50V

0.2ms

5.0V

0.2ms 100mV

The following waveforms were measured at the point of the corresponding

NOTE:

balloon number in the schematic diagram.

H-2

J702

HEADPHONE JACK

SP351

SPEAKER

J703

E-2

CRT

V801

J704

J705

SOUND AMP IC

IC1001 AN5277

127

11 5

FRONT VIDEO

J701

Q607

BUFFER

FRONT AUDIO L

FRONT AUDIO R

VIDEO AMP IC

IC801 TDA6108JF

PROTECT

Q403~Q406

FB401

Q606

42CVBS/Yin

BUFFER

OS101

P.CON+5V

P.CON+8V

B_IN

CVBSin

MUTE

IF_VO

S/SW

F_BLANK

G_IN

R_IN 46

C_IN

SAND

I_BLACK

R_OUT

G_OUT

B_OUT

5V REG. IC

IC501 KIA7805API

8V REG. IC

IC502 KIA7808API

MICON/CHROMA IC

IC101 TDA9365V5

BLOCK DIAGRAM

6 KEY_LED

X_TAL58X_TAL 59

X101

EEPROM IC

SCL

12MHz

IC199

S-24C16AFJA-TB-01

SDA 3

AGC

CF601

IF1

IF2 24

FILTER

VIF SAW

Q609

VIF PRE.AMP

SIFN 1

FILTER

SIF SAW

CF602

IF AMP

Q612

SIFN 2

PROTECTION

BCL

AC IN

H.OUTPUT

Q401

H.DRIVE

Q402

V+

V-

QSS_OUT

H_OUT

ALV/EW

PELAY

RY501

CD501

5 1

V.OUTPUT IC

IC401 LA78041

D501~D504

T501

H.CONTROL

Q453~Q455

POWER

Q511

Q502

RESET IC

IC901 R3111N311A/C-TR

TU001

TV/AV

DOWN

FUNCTION

STR

FEED BACK

IC506

T502

D529, D532

D533, D534

A2/NICAM/DOLBY IC

IC902 MSP3415G-QA-B8-V3

AT3.5V

AT+5.6V

H. CONTROL IC

20V REG.IC

IC451 TEA2031A

IC452 KIA78L20BP-AT

H.DRV+B

PS2561AL1-1-V(W)

F.BACK SW

Q507

+B ADJ.

VR501

E-1

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.

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