DOWNLOAD Panasonic TX-28PK20P Service Manual ↓ Size: 13.83 MB | Pages: 41 in PDF or view online for FREE

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.

5

±

0,25V B10

5

±

0,25V

12

±

0,5V

33

±

1,5V

15

±

1V

8

±

0,5V

B12 26

±

2V

6

±

1V

36

±

1,5V

13

±

1V

205

±

10V

14

±

1V

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."

Self-check is used to automatically check the bus lines and hexadecimal code of the TV set.To 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.

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

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 & TZS9EZ001
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.

VPC

O.K.

CIP

O.K.

SRC

O.K.

DDP

O.K.

TUN

O.K.

E2

O.K.

MSP

O.K.

DPL

- -

PCB

O.K.

Cab

O.K.

Sum

Factory use only

OPTION 1

3D

OPTION 2

7F

OPTION 3

0F

OPTION 4

40

OPTION 5

FD

OPTION 6

A1

Video Out
IC601 Pin 59

2V

64

µ

S

B - Out
E8 Pin 4

64

µ

S

4.6V

64

µ

S

2V

H - Pulse
Base Q503

VFLB
IC451 Pin 3

1V

20mS

B - Out
IC601 Pin 39

275

mV

64

µ

S

64

µ

S

3V

H - Out
IC601 Pin 50

Vert Out
IC601 Pin 31

20mS

0.7V

13

µ

S

3.7V

SCL
IC1201 Pin 3

R - Out
E8 Pin 5

64

µ

S

4.6V

HFLB
IC601 Pin 13

64

µ

S

6.2V

R - Out
IC601 Pin 37

64

µ

S

275

mV

G - Out
IC601 Pin 38

275

mV

64

µ

S

Vert Drive
IC451 Pin 2

20mS

57V

HFLB
IC701 Pin 8

64

µ

S

1.5V

G - Out
E8 Pin 3

64

µ

S

4.4V

SVM Out
IC601 Pin 34

88mV

64

µ

S

H - Out
IC701 Pin 5

30mV

64

µ

S

(The figures below are nominal and used for representative purposes only.)
1.  Set the Bass to maximum position, set the Treble to minimum position, press the volume down button

(-/v) on the customer controls at the front of the TV and at the same time press the INDEX button on the remote
control, this will place the TV into the Service Mode.

2. Press 

the 

RED / GREEN buttons to step up / down through the functions.

3. Press 

the 

YELLOW / BLUE buttons to alter the function values.

4. Press 

the 

STR button after each adjustment has been made to store the required values.

5.  To exit the Service Mode, press the "N" button.

Horizontal Position

H-Pos

061

Optimum setting.

Vertical Position

V-Pos

005

Optimum setting.

Horizontal Amplitude

H-Amp

055

Optimum setting.

Vert. Amplitude

V-Amp

054

Optimum setting.

EW-amplitude

E/W-Amp1

-128

Optimum setting.

EW-amplitude

E/W-Amp2

006

Optimum setting.

Trapezium-comp

Trapez-1

047

Optimum setting.

Trapezium-comp

Trapez-2

-128

Optimum setting.

Vertical Linearity

V-Lin

006

Optimum setting.

Vertical Symmetry

V-Sym

002

Optimum setting.

DVCO

DVCO

-005

Receive a PAL Colour Bar Pattern. For
DVCO alignment press "Blue" button, wait
until the colours are changing slowly and
press "STR".

Cut-off DC

Cut-off

0171

Ug2 Test

Ug2

055

O.K.

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."

Highlight

Lowlight

High

0902 0777 0864

Low

0117 0132 0112

Optimum setting.

Sub-Brightness

Sub-Brightness

255

Optimum setting.

Black Level

160V±5V

GND

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   CVBS 68