TX-28MD4P
Colour Television
TX-28MD4P
TX-25MD4P
TX-21MD4P
EURO4 Chassis
SPECIFICATIONS
(Information in brackets { } refers to model TX-25MD4P)
(Information in brackets [ ] refers to model TX-21MD4P)
Power Source: 220-240V AC, 50Hz
Power Consumption: 130W [115W]
Aerial Impedance: 75Ω unbalanced, Coaxial Type
Stand-by Power
Consumption: 1,8W
Receiving System: PAL B/G, H, D/K, PAL-525/60
SECAM B/G, D/K
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-E69 CATV (S01-S05)
CATV S1-S10 (M1-M10) CATV S11-S20 (U1-U10)
CATV S21-S41 (HYPERBAND)
Intermediate Frequency:
Video/Audio
Video 38,9MHz
Audio 33,4MHz, 33,16MHz
32,4MHz, 33,05MHz, 32,66MHz
Colour 34,47MHz (PAL)
34,5MHz, 34,65MHz (SECAM)
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
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) 1Vp-p 75Ω
Audio (21 pin) 500mV rms 1kΩ
Selectable output (21 pin)
AV3 IN Audio (RCAx2) 500mV rms 10kΩ
Video (RCAx1) 1V p-p 75Ω
High Voltage: 28,5kV ±1kV {28,2kV ±1kV}
[28kV ±1kV]
Picture Tube: A66ECF50X41 66cm
{A59ECF50X41 59cm}
[A51ECQ51X01 51cm]
Audio Output: 2 x 15W (Music Power)
8Ω Impedance
Headphones: 8Ω Impedance
3,5 mm
Accessories
supplied : Remote Control
2 x R6 (UM3) Batteries
Dimensions:
Height: 580 mm {531 mm} [478 mm]
Width: 666 mm {601 mm} [525 mm]
Depth: 472 mm {439 mm} [480 mm]
Net weight: 31kg {25kg} [22kg]
Specifications are subject to change without notice.
Weights and dimensions shown are approximate.
NOTE: This Service Manual should be used in conjunction with
the EURO4 Technical guide.
ORDER No. SM-98033
CONTENTS
SAFETY PRECAUTIONS..........................................................................................................................................................2
SERVICE HINTS.......................................................................................................................................................................3
ADJUSTMENT PROCEDURE...................................................................................................................................................4
ADJUSTMENT PROCEDURE AND SELF-CHECK ..................................................................................................................5
WAVEFORM PATTERN TABLE...............................................................................................................................................6
ALIGNMENT SETTINGS...........................................................................................................................................................7
BLOCK DIAGRAMS..................................................................................................................................................................8
PARTS LOCATION.................................................................................................................................................................12
REPLACEMENT PARTS LIST................................................................................................................................................ 13
SCHEMATIC DIAGRAMS.......................................................................................................................................................23
CONDUCTOR VIEWS.............................................................................................................................................................28
SAFETY PRECAUTIONS
GENERAL GUIDE LINES
1. It is advisable to insert an isolation transformer in the
AC 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 AC outlet.
5. Potentials as high as 29,5kV {29,2kV} [29kV] 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 AC 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 AC 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 AC cord directly into the AC 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 AC 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 AC plug at the outlet and repeat each of
the above measurements.
6. The potential at any point should not exceed
1,4 Vrms. 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.
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 29,5kV 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.
TX-28MD4P 28,5kV ± 1kV.
TX-25MD4P 28,2kV ± 1kV.
TX-21MD4P 28kV ± 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.
HOT CHECK CIRCUIT
A.C. VOLTMETER
WATER PIPE
(
EARTH)
TO INSTRUMENT’S EXPOSED
METALLIC PARTS
Fig. 1.
2k
Ω
10 Watts
2
SERVICE HINTS
How to remove the rear cover
1. Remove the 9 screws as shown in Fig.2.
LOCATION OF CONTROLS
3
SCREWS
Fig.2.
E-BOARD
Y-BOARD
FOCUS
SCREEN
H-BOARD
Fig.3.
ADJUSTMENT PROCEDURE
The remote control is used for entering and storing adjustments, with the exception of Cut-off adjustments, which must
always be done prior to service adjustment. Perform adjustments in accordance with screen display. The display on the
screen also specifies the software version as well as the approx. setting values. The adjustment sequence for the service
mode is indicated below.
1. Set the Bass to maximum position, set the Treble to
minimum position, press the F button followed by the
volume down button 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.
NOTE: This TV also has the option of using a Memory Pack which enables you to copy the preset TV channels into the
Memory Pack and then download them onto this or any other EURO-4 TV set.
TV to Memory Pack process
1. Plug the memory pack into the AV1 21 pin terminal at
the back of the TV and switch the TV on.
2. Go into Service Mode as explained above.
The screen will show :-
3. Press the BLUE button on the remote control.
The screen will show :-
4. Press the STR button on the TV.
The screen will show :-
5. All the tuning information stored inside the TV will
now be transferred to the Memory Pack. This process
will take 2-3 minutes to complete and when finished
the screen will show :-
Memory Pack to TV process
1. Plug the memory pack into the AV1 21 pin terminal at
the back of the TV and switch the TV on.
2. Go into Service Mode as explained above.
The screen will show :-
3. Press the STR button on the TV.
The screen will show :-
4. All the tuning information stored inside the Memory
Pack will now be transferred to the TV. This process
will take 2-3 minutes to complete and when finished
the screen will show :-
5. The tuning information from the Memory Pack has
now been copied into the TV.
6. To exit from the Service Mode press the "N" button.
7. The process has now been completed and the
Memory Pack can now be removed.
ERRORS
If an error occurs while using the Memory Pack the TV will detect this and the screen will show :-
If this happens then press the "N" button and repeat the process that was being used. If the errors continue to occur then
check the connectors between the TV and the memory pack and check the 9V battery inside the memory pack.
Program
External>>TV
Program
TV>>External
Please Wait
Complete
Program
External>>TV
Please Wait
Complete
Error !!
4
Error !!
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 [130V±1V
TX-21MD4P]
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, 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
Self-check is used to automatically check the bus lines and hexadecimal code of the TV set. To get into the Self-Check mode
press the down (-/v) button on the customer controls at the front of the set, at the same time pressing the STATUS button on
the remote control, and the screen will show :-
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
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.
VDP O.K.
TUN O.K.
E2 O.K.
MSP O.K.
--
PCB O.K.
Cab O.K.
Sum
Factory use only
OPTION 1 3D [3D]
OPTION 2 0C [0E]
OPTION 3 1F [1F]
OPTION 4 00 [00]
OPTION 5 EF [EF]
OPTION 6 21 [21]
5
WAVEFORM PATTERN TABLE
6
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
275mV
64
µ
S
64
µ
S
3V
H - Out
IC601 Pin 50
Vert Out
IC601 Pin 31
20mS
0.7V
13µS
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
275mV
G - Out
IC601 Pin 38
275mV
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
64µS
H - Out
IC701 Pin 5
30mV
64
µ
S
ALIGNMENT SETTINGS
(The figures below are nominal and used for representative purposes only.)
Alignment Function Settings / Special features
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, 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.
7
Black Level
160V±5V
GND
VIDEO BLOCK DIAGRAM
Q105
AV1
IC601
9LGHR
2XW
9LGHR
,Q
AV2
AV3
Q3601
IC1101
R 37
68
CVBS
61 V IN 1
43 B IN
42 G IN
41 R IN
62 VIN 2
60 C IN
63 VIN 3
VIN 4
64
VIDEO OUT
59
B IN 47
B OUT 39
Q303
Q301
E8
4
3
5
Q353
Q35
2
Q35
1
CRT
3
2
1
7
8
9
Y2
4
3
5
IC351
Q104
5HG
%OXH
*UHHQ
9LGHR
,Q
$9
&
9LGHR
2XW
G OUT 38
R OUT 37
G IN 46
R IN 45
Q304
Q302
Q35
4
7
7
VM
COILS
Q905 Q907 Q909
Q908Q906
SVM OUT 34
Q950 Q951
Q3001
G 38
B 39
Y - BOARD
E - BOARD
RGB
OUTPUT
VIDEO
PROCESSOR
MICRO
PROCESSOR
H3
E61
E15
1
6
8
H1
1
6
8
H - BOARD
TX-28MD4P
TX-25MD4P
ONLY
TX-28MD4P
TX-25MD4P
ONLY
8
IC3401
Q3402
8
6
3
VIDEO
SWITCHING
AUDIO BLOCK DIAGRAM
TUNER
Q101
Q102
IC2101
IC251
Q2102
Q2103
AV3
AV1
DACM_R 24
SC3_IN_L 37
SC1_OUT_R 30
SC1_OUT_L 31
5 R
L
R
R 7
6 R
1 R OUT
3 L OUT
1 R OUT
3 L OUT
2 R IN
6 L IN
2 R IN
6 L IN
47 ANA_IN1+
DACM_L 25
SC3_IN_R 38
SC1_IN_R 42
SC1_IN_L 41
SC2_OUT_R 27
SC2_OUT_L 28
SC2_IN_R 40
SC2_IN_L 39
Q252
Q251
2 L
L 11
4 L
HEADPHONE
7 R
5 L
E6
1
E7
3
Q2304
Q2302
21 DACA_R
22 DACA_L
E - BOARD
AUDIO
PROCESSOR
AUDIO
OUTPUT
AUDIO
MONITOR
OUT
Q2303
Q2301
9
CONTROL BLOCK DIAGRAM
H3
3
E63
1
E18
6
5
4
SDA 1
SCL 1
SDA 2
SCL 2
SERVICE / TEST
IC2101
IC1101
TUNER
IC601
IC1103
6
5
50
SCL 2
SDA 2
4
3
SDA 1
SCL 1
SCL
SDA
48
49
8
7
4
5
IC3401
71
LOCAL
KEYS
SWITCH
MATRIX
60
52
74
IC1051
81
AV2
8
10
AV1
8
10
12
75
51
72
73
AV LINK
SLOW 2
SLOW 1
SCL 1
SDA 1
59
58
55
VPROT
KEYSCAN
ON/OFF
R.C.
L.E.D.
PROT 1
SLOW 2
OUT
IN
SLOW 1
SERVICE
SCL
SDA
H - BOARD
E - BOARD
VIDEO
SWITCHING
AUDIO
PROCESSOR
MICRO
PROCESSOR
VIDEO
PROCESSOR
EAROM
REMOTE
CONTROL
RECEIVER
10
3
Loading...