TX-28MK1LM - Panasonic TV Service Manual (repair manual)

tx-28mk1lm service manual
Model
TX-28MK1LM
Pages
27
Size
3.12 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / EURO-4
File
tx-28mk1lm.pdf
Date

Read Panasonic TX-28MK1LM Service Manual online

Service Support
Service and repair of this
product is supported by
Panasonic's LUCI interface.
This interface provides
a link between the TV and
a standard PC to ow a
number of diagnostic and
control functions to be
performed.
For more details contact
your local Panasonic company.
TX-28MK1L/M Service Manual
Specifications
Parts List
Safety
Block
Diagrams
Exploded
View
PCB
Views
Service
Information
Schematic
Diagrams
BACK
EXIT
Colour Television
TX-28MK1L/M
EURO-4 Chassis
SPECIFICATIONS
Power Source:
220-240V a.c., 50Hz
Power Consumption:
85W
Stand-by Power
Consumption:
1,8W
Aerial Impedance:
75
 unbalanced, Coaxial Type
Receiving System:
PAL I, (UHF/VHF) PAL-525/60
M.NTSC
NTSC (AV only)
Receiving Channels:
UHF E21-E69
VHF A1 - S20
Intermediate Frequency:
Video/Audio
Video
39,5MHz
Audio
33,5MHz
32,95MHz (NICAM)
Colour
35,07MHz
Terminals:
AUDIO MONITOR OUT
Audio (RCAx2) 500mV rms 1k
AV1 IN
Video (21 pin) 1V p-p 75
Audio (21 pin) 500mV rms 10k
RGB (21 pin)
AV1 OUT
Video (21 pin) 1V p-p 75
Audio (21 pin) 500mV rms 1k
AV2 IN
Video (21 pin) 
1V p-p 75
Audio (21 pin) 
500mV rms 10k
S-Video IN
Y: 1V p-p 75
(21-pin)
C:0,3V p-p 75
AV2 OUT
Video (21 pin) 
1V p-p 75
Audio (21 pin)
500mV rms 1k
Selectable output (21 pin)
AV3 IN
Audio (RCAx2)
500mV rms 10k
Video (RCAx1)
1V p-p 75
High Voltage:
28,2kV 
±
 1kV
Picture Tube:
A66ECF50X42
66cm
Audio Output:
2 x 15W (Music Power)
8
 Impedance
Headphones:
8
 Impedance
3,5 mm
Accessories
supplied :
Remote Control
2 x R6 (UM3) Batteries
T.V. Stand TS2800 / TS2800S
Dimensions:
Height:
580mm
Width:
666mm
Depth:
472mm
Net weight:
31kg
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.
ORDER No. SM-99046
CONTENTS
SAFETY PRECAUTIONS..........................................................................................................................................................2
SERVICE HINTS .......................................................................................................................................................................3
SERVICE POSITION.................................................................................................................................................................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 .......................................................................................................................................................22
CONDUCTOR VIEWS.............................................................................................................................................................27
SAFETY PRECAUTION
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 
2k
 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
1,4 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 29,2kV 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.
HOT CHECK CIRCUIT
a.c. VOLTMETER
WATER PIPE
(EARTH)
TO INSTRUMENT’S EXPOSED
METALLIC PARTS
Fig. 1.
2k
 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.
Page of 27
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Here you can read online and download Panasonic TX-28MK1LM Service Manual in PDF. TX-28MK1LM service manual will guide through the process and help you recover, restore, fix, disassemble and repair Panasonic TX-28MK1LM TV. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.