1 Safety Precautions
1.1.
General Guidelines
6
1.2.
1. When conducting repairs and servicing, do not attempt to modify the equipment, its parts or its materials.
2. When wiring units (with cables, flexible cables or lead wires) are supplied as repair parts and only one wire or some of the
wires have been broken or disconnected, do not attempt to repair or re-wire the units. Replace the entire wiring unit instead.
3. When conducting repairs and servicing, do not twist the Faston connectors but plug them straight in or unplug them straight
out.
4. When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated or
damaged by the short circuit.
5. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly
installed.
After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.
Touch-Current Check
1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.
2. Connect a measuring network for touch currents between each exposed
metallic part on the set and a good earth ground
such as a water pipe, as shown in Figure 1.
3. Use Leakage Current Tester (Simpson 228 or equivalent) to measure the potential across the measuring network.
4. Check each exposed metallic part, and measure the voltage at each point.
5. Reserve the AC plug in the AC outlet and repeat each of the above measure.
6. The potential at any point (TOUGH CURRENT) expressed as voltage U
1
and U
2
, does not exceed the following values:
For a. c.: U
1
= 35 V (peak) and U
2
= 0.35 V (peak);
For d. c.: U1 = 1.0 V,
Note:
The limit value of U
2
= 0.35 V (peak) for a. c. and U
1
= 1.0 V for d. c. correspond to the values 0.7 mA (peak) a. c. and 2.0
mA d. c.
The limit value U
1
= 35 V (peak) for a. c. correspond to the value 70 mA (peak) a. c. for frequencies greater than 100 kHz.
7. In case a measurement is out of the limits specified, there is a possibility of a shock hazard, and the equipment should be
repaired and rechecked before it is returned to the customer.
Measuring network for TOUCH CURRENTS
COLD
WATER PIPE
(EARTH GROUND)
Rs=
1500Q
_ L Cs=
0.22|
j
F
10kQ
-1
k
1
-------
1
Ro=
----------------
J
500Q
'
U
1
=
r
= 0.022|jF
( V )
J Q
L jJ J U U i i
U 1 — |— и . и ^ г ф Г
^ V
J
| U
2
(V)
APPLIANCES
EXPOSED
METAL PARTS
Resistance values in ohms (Q)
V:
Voltmeter or oscilloscope
(r.m.s. or peak reading)
Input resistance:
> 1 MQ
Input capacitance: < 200 pF
Frequency range: 15 Hz to 1 MHz and d.c. respectively
NOTE - Appropriate measures should be taken to obtain the correct value in case of non-sinusoidal waveforms.
Figure 1
3
Summary of Contents for Viera TX-P42U20B
Page 21: ...7 4 No Picture 21...
Page 33: ...11 Block Diagram 11 1 Main Block Diagram 33...
Page 34: ...11 2 Block 1 4 Diagram 34...
Page 35: ...G 0 11 3 Block 2 4 Diagram I A I D IG IT A L S IG N A L P R O C E S S O R 35...
Page 36: ...11 4 Block 3 4 Diagram P P O W E R S U P P LY 36...
Page 38: ...38...
Page 40: ...12 3 Wiring 2 40...
Page 43: ...13 2 P Board 1 4 Schematic Diagram A B C D E A P BO ARD LSEP1287BE HB 1 4 F 1 2 3 4 42...
Page 44: ...13 3 P Board 2 4 Schematic Diagram A P BO ARD LSEP1287BE HB 2 4 10 11 12 13 14 15 16 17 18 43...
Page 45: ...13 4 P Board 3 4 Schematic Diagram A B C D E F 1 2 3 4 44 5...
Page 46: ...13 5 P Board 4 4 Schematic Diagram 10 11 12 13 14 15 16 17 18 45...
Page 47: ...13 6 A Board 1 19 Schematic Diagram A A A BO AR D 1 19 IIC B C D E F 1 2 3 4 9 46...
Page 52: ...13 11 Board 6 19 Schematic Diagram A A BO AR D 6 19 STB MPU 46 47 48 49...
Page 54: ...13 12 Board 7 19 Schematic Diagram A A BO AR D 7 1 9 HDMI 55 56 57 58 59 52...
Page 55: ...60 61 62 63...
Page 57: ...69 70 71 72...
Page 60: ...87 8 8 89 90...
Page 61: ...13 16 A Board 11 19 Schematic Diagram A A BO AR D 11 19 A V SW 91 92 93 94 95 96 97 98 99 56...
Page 63: ...FE_Virtual_M odule Peaks COMMON TO 3 19 Analog ASIC 104 105 106 107 108 57...
Page 68: ...140 141 142 143 144 61...
Page 71: ...63...
Page 72: ...13 24 A Board 19 19 Schematic Diagram A A BO AR D 19 19 DVB T C D EM O D U LATO R 64...
Page 75: ...13 27 C2 Board 1 2 Schematic Diagram A A C 2 BO AR D TN PA5095 1 2 ___ I TO A BOARD A32 B 67...
Page 78: ...13 30 SC Board 2 4 Schematic Diagram 10 I 11 1 12 1 13 1 14 1 15 1 16 1 17 1 18 70...
Page 79: ...13 31 SC Board 3 4 Schematic Diagram 19 1 20 1 21 1 22 1 23 1 24 1 25 1 26 1 27 71...
Page 80: ...13 32 SC Board 4 4 Schematic Diagram 28 29 30 31 32 33 34 35 36 72...
Page 86: ...P BOARD COMPONENT SIDE LSEP1287BEHB B G 6 5 4 3 2 1 E F H 77...
Page 88: ...14 3 A Board 79...
Page 89: ...A BOARD COMPONENT SIDE A P42U20B A P42U20E A PR42U20 B G 6 5 4 3 2 1 E F H 80...
Page 92: ...14 6 SC Board SC BOARD FOIL SIDE TXNSC11DEK B G 6 5 4 3 2 1 E F H 83...
Page 93: ...SC BOARD COMPONENT SIDE TXNSC11DEK 6 5 4 3 2 1 A I b I C I d I E I F I G I H I I 84...
Page 94: ...14 7 SS Board SS BOARD FOIL SIDE TXNSS11DEK 6 5 4 3 2 1 A I b I C I d I E I F I G I H I I 85...
Page 95: ...SS BOARD COMPONENT SIDE TXNSS11DEK...
Page 96: ......
Page 98: ...15 1 2 Exploded View 2 88...
Page 99: ...89...
Page 100: ...15 1 4 Packing 2 90...