Panasonic TX-25MK1 Service Manual

SPECIFICATIONS

Power Source: 220-240V a.c., 50Hz
Power Consumption: 85W
Stand-by Power

Consumption: 1,8W
Aerial Impedance: 75Ω unbalanced, Coaxial Type
Receiving System: PAL I, PAL-525/60

M.NTSC
NTSC (AV only)

Receiving Channels: UHF E21-E69
Intermediate Frequency:

Video/Audio

Video 39,5MHz
Audio 33,5MHz

32,95MHz (NICAM)

Colour 35,07MHz

Terminals:

AUDIO MONITOR OUT Audio (RCAx2) 500mV rms 1kΩ
AV1 IN Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500mV rms 10kΩ
RGB (21 pin)

AV1 OUT Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500mV rms 1kΩ

ORDER No. 99-SM-001

Colour Television

TX-25MK1

EURO-4 Chassis

AV2 IN Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500mV rms 10kΩ
S-Video IN Y: 1V p-p 75Ω
(21-pin) C:0, 3V p-p 75Ω

AV2 OUT Video (21 pin) 1V p-p 75Ω

Audio (21 pin) 500m V rms 1kΩ
Selectable output (21 pin)

AV3 IN Audio (RCAx2) 500mV rms 10kΩ

Video (RCAx1) 1V p-p 75Ω

High Voltage: 28,2kV ± 1kV
Picture Tube: A59ECF50X42 59cm

Audio Output: 2 x 15W (Music Power)

8Ω Impedance

Headphones: 8Ω Impedance

3,5mm

Accessories
supplied : Remote Control

2 x R6 (UM3) Batteries
T.V. Stand TS2800

Dimensions:

Height: 535mm
Width: 601mm
Depth: 440mm

Net weight: 25kg
Specifications are subject to change without notice.

Weights and dimensions shown are approximate.
NOTE: This Service Manual should be used in conjunction with

the EURO-4 Technical guide.

Panasonic CS ( U.K. ) Ltd.

WILLOUGHBY ROAD,

BRACKNELL,

BERKS.,

RG12 8FT.

CONTENTS

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

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

SERVICE POSITION.................................................................................................................................................................4

ADJUSTMENT PROCEDURE AND FACTORY SETTINGS.....................................................................................................5

WAVEFORM PATTERN TABLE...............................................................................................................................................6

ALIGNMENT SETTINGS...........................................................................................................................................................7

BLOCK DIAGRAMS..................................................................................................................................................................8

PARTS LOCATION.................................................................................................................................................................12

REPLACEMENT PARTS LIST................................................................................................................................................13

SCHEMATIC DIAGRAMS.......................................................................................................................................................22

CONDUCTOR VIEWS.............................................................................................................................................................26

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 29,2kV 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

2kΩ 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 29,2kV 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.
28,2kV ± 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)

2

SERVICE HINTS

How to remove the rear cover

1. Remove the 9 screws as shown in Fig.2.

LOCATION OF CONTROLS

SCREWS

Fig.2.

E-BOARD Y-BOARD

H-BOARD

Fig.3.

3

FOCUS
SCREEN

HOW TO MOVE THE CHASSIS INTO SERVICE POSITION

(A)

1. Remove the bead clamper from the mains lead and attach to the degauss coil, shown in Fig.5.

2. Hold and lift the rear of the E-PCB chassis and gently pull the chassis toward you, as shown in Fig.4.

3. Release the respective wiring clips and rotate the chassis horizontally through 90°, anti-clockwise.

4. Move the EHT lead around to the left side of the CRT neck.

5. Elevate the front of the chassis.

6. Clip the chassis frame onto the bead clamper, on the degauss coil, as shown in Fig.5.

7. Locate the base of the chassis frame into the hole (marked A), shown in Fig.6.

8. After servicing replace the bead clamper and ensure all wiring is returned to its original position before returning the
receiver to the customer.

Fig.5.

Fig.4.

Fig.6.

4

ADJUSTMENT PROCEDURE

Item / Preparation Adjustments
+B SET-UP

1. Receive a Greyscale signal.

2. Set the controls :-

Brightness Minimum
Contrast Minimum
Volume Minimum

1. Set the +B voltage up as follows:­Adjust R811 so that B2 shows 148V±1V.

2. Confirm the following voltages.

B9 5 ± 0,25V B10 5 ± 0,25V
B5 12 ± 0,5V B11 33 ± 1,5V
B4 16 ± 1V B7 8 ± 0,5V
B12 26 ± 1V B8 5,5 ± 0,5V
B3 35 ± 1V B13 15 ± 1V
B1 200 ± 10V B14 -15 ± 1V

CUT OFF / Ug2 Test

1. Receive a Greyscale signal.

2. Degauss the tube externally.

3. Set the TV into Service Mode 1.

4. Select Cut off mode.

To adjust Cutoff connect an oscilloscope to the Blue
cathode.Press "STR" and adjust "cutoff" value using the
"Yellow" and "Blue" buttons until the black level is 160V±5V,
press "STR" to store the value. Remove the oscilloscope.
Select Ug2 adjustment and adjust the screen VR until the
display shows "O.K."

FACTORY SETTINGS

To return customer settings to factory settings and clear owner ID of all information input by the customer, enter Self-Check
mode. Press the down (-/v) button on the customer controls at the front of the TV set, at the same time pressing the STATUS
button on the remote control. To exit Self Check, switch off the TV set at the power button.

NOTE: Self Check should only be used when refurbishing the TV set and not during normal repair work.

VDP O.K.
TUN O.K.
E2 O.K.
MSP O.K.

--

OPTION 1 00
OPTION 2 00

PCB O.K.
Cab O.K.
Sum Factory use only

OPTION 3 02
OPTION 4 00
OPTION 5 A1
OPTION 6 A9

If the CCU ports have been checked and found to be incorrect or not located then " - - " will appear in place of "O.K.".

Service Aids

To aid in the service of our current chassis there are a number of Service Aids which have been made available.

• LUCI interface kit (Linked Utility Computer Interface)
Part number: TZS6EZ002
This contains interface and cables for connecting TV service connector and a PC as well as diagnostic software. As new
models are introduced upgrade software will become available.

• VICI (Visual Interactive Computer Information)
These C.D.'s contain multimedia documentation providing quick access to service information.
Part No. TZS7EZ006, TZS7EZ005 & TZS8EZ001

1. Service Manuals

2. Instruction Books

3. Technical Information

• TASMIN (Technically Advanced System for Multimedia Interactive Notes)
As well as providing a first step towards more interactive training this product also achieves quick access to Technical
Information.

5

WAVEFORM PATTERN TABLE

Vert Out
IC601 Pin 31

0.7V

H - Out
IC601 Pin 50

3V

HFLB
IC601 Pin 13

6.2V

20mS

64µS

Vert Drive
IC451 Pin 2

57V

H - Out
IC701 Pin 5

30mV

HFLB
IC701 Pin 8

1.5V

20mS

64µS

VFLB
IC451 Pin 3

1V

20mS

H - Pulse
Base Q503

2V

64µS

Video Out
IC601 Pin 59

2V

R - Out
IC601 Pin 37

275mV

R - Out
E8 Pin 5

4.6V

SCL
IC1201 Pin 3

64µS

64µS

64µS

G - Out
IC601 Pin 38

275mV

G - Out
E8 Pin 3

4.4V

SVM Out
IC601 Pin 34

64µS

64µS

64µS

64µS

B - Out
IC601 Pin 39

275mV

64µS

B - Out
E8 Pin 4

4.6V

64µS

3.7V
88mV

13µS

64µS

6

ALIGNMENT SETTINGS

(The figures below are nominal and used for representative purposes only.)

Alignment Function Settings / Special features

Horizontal Position

Vertical Position

Horizontal Amplitude

Vert. Amplitude

EW-amplitude

EW-amplitude

Trapezium-comp

Trapezium-comp

H-Pos

061

V-Pos

005

H-Amp

055

V-Amp

054

E/W-Amp1

-128

E/W-Amp2

006

Trapez-1

047

Trapez-2

-128

Optimum setting.

Optimum setting.

Optimum setting.

Optimum setting.

Optimum setting.

Optimum setting.

Optimum setting.

Optimum setting.

Vertical Linearity

Vertical Symmetry

DVCO

Cut-off DC

Ug2 Test

Highlight

Lowlight

V-Lin

006

V-Sym

002

DVCO

-005

Cut-off

0171

Ug2

055

O.K.

High 0902 0777 0864
Low 0117 0132 0112

Optimum setting.

Optimum setting.

Receive a PAL Colour Bar Pattern. For
DVCO alignment press "Blue" button, wait
until the colours are changing slowly and
press "STR".
To adjust Cutoff connect an oscilloscope to
the blue cathode. Press "STR" and adjust
"cutoff" value using the "Yellow" and
"Blue" buttons until the black level is
160V±5V press "STR" to store the value.
Remove the oscilloscope.
Select Ug2 adjustment and adjust the
screen VR until the display shows "O.K."

Black Level
160V±5V
GND

Optimum setting.

Sub-Brightness

Sub-Brightness

255

7

Optimum setting.

VIDEO BLOCK DIAGRAM

,Q

Q35





,Q

&



Q35

8

AV1

9LGHR2XW

%OXH

*UHHQ

5HG

9LGHR

AV2

9LGHR

$9

E - BOARD











Q105

Q104

61 V IN 1

43 B IN
42 G IN
41 R IN

62 VIN 2

63 VIN 3

60 C IN

VIN 4

64

IC601

VIDEO

PROCESSOR

VIDEO OUT
59

Q3601

SVM OUT 34

B OUT 39

G OUT 38

R OUT 37

B IN 47

G IN 46

R IN 45

Q950 Q951

Q303

Q304

Q301

Q302

E8

Q908Q906

Q905 Q907 Q909

7

7

4

4

3

IC351

7

Q353

VM

COILS

RGB

Y - BOARD

4

OUTPUT

2

1

CRT

2

8

9

1

3

3

5

5

Y2

2XW

9LGHR

AV3

Q3001

68
CVBS

IC1101

MICRO

PROCESSOR

R 37

G 38
B 39

E15

6

8

1

E61

H - BOARD

H1

6

8

1

H3

Q3402

IC3401

8

VIDEO

SWITCHING

6

3

AUDIO BLOCK DIAGRAM

9

E - BOARD

TUNER

Q101

Q102

IC2101

PROCESSOR

47 ANA_IN1+

AUDIO

DACM_R 24

SC3_IN_L 37

SC3_IN_R 38

SC1_OUT_R 30

SC1_IN_R 42

SC1_OUT_L 31

SC1_IN_L 41

DACM_L 25

Q2102

Q2103

Q252

Q251

5 R

2 L

IC251
AUDIO

OUTPUT

R 7

L 11

E6

1

E7

3

AV3

6 R
7 R

HEADPHONE
5 L
4 L

L
R

1 R OUT

2 R IN

3 L OUT

6 L IN

AUDIO

MONITOR

OUT

Q2303

Q2301

Q2304
Q2302

21 DACA_R
22 DACA_L

SC2_OUT_R 27

SC2_IN_R 40

SC2_OUT_L 28

SC2_IN_L 39

AV1

1 R OUT

2 R IN

3 L OUT

6 L IN