Read Panasonic TX-21RX20T Service Manual online
Power Source :
AC SINGLE 220-240 V, 50/60 Hz
Power Consumption :
86 W
Aerial Impedance :
75
Ω unbalanced
Coaxial type
Receiving System :
17 Systems
SYSTEMS
FUNCTIONS
———————————————————————————————
1
PAL B, G, H
2
PAL I
Reception
of broadcast
playback from
video cassette tape
recorders.
3
PAL D, K
4
SECAM B, G
5
SECAM D, K
6
SECAM K1
7
NTSC M
(NTSC 3.58 / 4.5 MHz)
———————————————————————————————
8
NTSC 4.43 / 5.5 MHz
9
NTSC 4.43 / 6.0 MHz
10
NTSC 4.43 / 6.5 MHz
11
NTSC 3.58 / 5.5 MHz
Playback from
special VCR only.
12
NTSC 3.58 / 6.0 MHz
13
NTSC 3.58 / 6.5 MHz
14
SECAM I
———————————————————————————————
15
PAL 60 Hz / 5.5 MHz
Playback from
special Disc player
and VCR only.
16
PAL 60 Hz / 6.0 MHz
17
PAL 60 Hz / 6.5 MHz
TX-21RX20T
GP41Z Chassis
Receiving Channels :
VHF
2-12 PAL / SECAM B, K1
0-12 PAL B (AUST)
1-9 PAL B (N. ZEALAND)
1-12 PAL / SECAM D
1-12 NTSC M (JAPAN)
2-13 NTSC M (U.S.A.)
UHF
21-69 PAL G, H, I / SECAM G, K, K1
28-69 PAL B (AUST)
13-57 PAL D, K
13-62 NTSC M (JAPAN)
14-69 NTSC M (U.S.A.)
CATV
S1-S20 (OSCAR)
1-125 (U.S.A. CATV)
C13-C49 (JAPAN)
S21-S41 (HYPER)
Z1-Z37 (CHINA)
5A, 9A (AUST)
Tuning System :
Frequency synthesizer
Auto search tuning : 100 position
Colour Television
Specifications
ORDER NO. MTV0801643CE
Video / Audio Terminal :
DVD
Y
1.0 Vp-p 75
Ω
P
B
0.7 Vp-p 75
Ω
P
R
0.7 Vp-p 75
Ω
AV 1, 2, 3
Video In
1 Vp-p 75
Ω
Audio In
Approx. 0.5 V, 47 k
Ω
Monitor Out
Video Out
1 Vp-p 75
Ω
Audio Out
Approx. 0.5 V, 1 k
Ω
Picture Tube :
Viewable Picture tube measured
diagonally : 51 cm
Measured diagonally,
1 Safety Precautions
3
1.1.
General Guidelines
3
1.2.
Leakage Current Cold Check
3
1.3.
Leakage Current Hot Check (Fig. 1)
3
1.4.
X-Radiation
4
1.5.
SW-Board Fix to Cabinet
4
1.6.
GP41Z Chassis Block Diagram
5
2 Service Hints
6
2.1.
Service Position for E-Board
6
2.2.
Service Mode Explanation
6
2.3.
Adjustment for White Balance
7
2.4.
Adjustment for CRT CUT OFF
7
2.5.
Adjustment Procedure
7
2.6.
Adjustment of Purity
8
3 Location of Lead Wiring
20
3.1.
Wire Dressing
20
90° deflection
Audio Output :
10 W x 2 = 20 W
Operating Conditions :
Temperature :
0°C - 35°C
Humidity :
20°C - 80°C RH (non-condensing)
Dimensions :
Height : 431 mm
Width : 596 mm
Depth : 340 mm
Mass :
20.5 kg (Net)
Specifications are subject to change without notice.
Mass and dimensions shown are approximate.
Mass and dimensions shown are approximate.
3.2.
Wire Dressing and Connections
21
4 Conductor Views
22
5 Schematic Diagram
23
5.1.
A Board
25
5.2.
L Board
30
5.3.
V Board
33
5.4.
G Board
35
5.5.
P Board
37
5.6.
K Board
38
5.7.
SW Board
39
6 Parts Locations
41
6.1.
Packing Exploded View - A
41
6.2.
Packing Exploded View - B
42
6.3.
Parts Locations
43
7 Replacement Parts List
44
7.1.
Replacement Parts List
45
CONTENTS
Page
Page
2
TX-21RX20T
1 Safety Precautions
1.1. General Guidelines
1. It is advisable to insert an isolation transformer in the AC supply before servicing this hot chassis.
2. When servicing, observe the original lead dress, especially the lead dress in the high voltage circuits. If a short circuit is found,
2. When servicing, observe the original lead dress, especially the lead dress in the high voltage circuits. If a short circuit is found,
replace all parts which have been overheated or damaged by the short circuit.
3. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers, shields and isolation R-C
combinations are properly installed.
4. When the receiver is not to be used for a long period of time, unplug the power cord from the AC power socket.
5. Potential, as high as 25.0 kV is present when this receiver is in operation. Operation of the receiver without the rear cover
5. Potential, as high as 25.0 kV is 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
thoroughly familiar with the precautions necessary when working on high voltage equipment. Always discharge the anode of the
picture tube to the receiver chassis before handling the tube. After servicing, make the following leakage current check to
prevent the customer from being exposed to shock hazards.
thoroughly familiar with the precautions necessary when working on high voltage equipment. Always discharge the anode of the
picture tube to the receiver chassis before handling the tube. After servicing, make the following leakage current check to
prevent the customer from being exposed to shock hazards.
1.2. Leakage Current Cold Check
1. Unplug the power cord and connect a jumper between the two prongs on the plug.
2. Turn on the receiver’s power switch.
2. Turn on the receiver’s power switch.
Measure the resistance value, with an ohmmeter, between the jumper 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 4 M
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 4 M
Ω and 20 MΩ. When the exposed metal does not have a return path to the chassis, the
reading must be infinite.
1.3. Leakage Current Hot Check (Fig. 1)
1. Plug the power cord directly into the power socket. Do not use an isolation transformer for this check.
2. Check that a 2 k
2. Check that a 2 k
Ω non-inductive resistor and an AC/DC current meter are in series with each exposed metallic part on the
receiver in turn and an earth such as a water pipe.
The current from any point should not exceed 0.7 mA peak AC or 2 mA DC. In the case of a measurement being outside of
these 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.
The current from any point should not exceed 0.7 mA peak AC or 2 mA DC. In the case of a measurement being outside of
these 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.
Fig. 1
3
TX-21RX20T
1.4. X-Radiation
Warning:
The potential sources of X-Radiation in TV set are the EHT section and the picture tube. When using a picture tube test jig for
service, ensure that the jig is capable of handling 25.5 kV without causing X-Radiation.
Note: It is important to use an accurate periodically calibrated high voltage meter.
1. Set the brightness to minimum.
2. Use the remote to get into Service Mode.
3. Measure the EHT. The meter reading should indicate 24.0 ± 1.5 kV. If the meter indication is out of tolerance, immediate
The potential sources of X-Radiation in TV set are the EHT section and the picture tube. When using a picture tube test jig for
service, ensure that the jig is capable of handling 25.5 kV without causing X-Radiation.
Note: It is important to use an accurate periodically calibrated high voltage meter.
1. Set the brightness to minimum.
2. Use the remote to get into Service Mode.
3. Measure the EHT. The meter reading should indicate 24.0 ± 1.5 kV. If the meter indication is out of tolerance, immediate
service and correction are required to prevent the possibility of premature component failure.
4. To prevent the possibility of X-Radiation, it is essential to use the specified picture tube, if service replacement becomes
necessary.
1.5. SW-Board Fix to Cabinet
4
TX-21RX20T