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,
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
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.
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.
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
Ω
and 20 M
Ω
. 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
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.
Fig. 1
3
TX-21RX20M-MALAYSIA
Summary of Contents for TX-21RX20M-MALAYSIA
Page 20: ...3 Location of Lead Wiring 3 1 Wire Dressing 20 TX 21RX20M MALAYSIA...
Page 22: ...4 Conductor Views 22 TX 21RX20M MALAYSIA...
Page 25: ...5 1 A Board 5 1 1 A Board 1 5 1A 2A 3A 5A 4A 6A 7A 8A 25 TX 21RX20M MALAYSIA...
Page 26: ...5 1 2 A Board 2 5 1B 2B 3B 4B 5B 6B 7B 1A 2A 3A 5A 4A 6A 7A 8A 26 TX 21RX20M MALAYSIA...
Page 27: ...5 1 3 A Board 3 5 1C 2C 3C 4C 5C 6C 8C 7C 1B 2B 3B 4B 5B 6B 7B 27 TX 21RX20M MALAYSIA...
Page 28: ...5 1 4 A Board 4 5 1D 2D 3D 4D 5D 7D 8D 9D 6D 1C 2C 3C 4C 5C 6C 8C 7C 28 TX 21RX20M MALAYSIA...
Page 29: ...5 1 5 A Board 5 5 1D 2D 3D 4D 5D 7D 8D 9D 6D 29 TX 21RX20M MALAYSIA...
Page 30: ...5 2 L Board 5 2 1 L Board 1 3 1A 2A 3A 4A 5A 30 TX 21RX20M MALAYSIA...
Page 31: ...5 2 2 L Board 2 3 1B 2B 3B 4B 1A 2A 3A 4A 5A 31 TX 21RX20M MALAYSIA...
Page 32: ...5 2 3 L Board 3 3 1B 2B 3B 4B 32 TX 21RX20M MALAYSIA...
Page 33: ...5 3 V Board 5 3 1 V Board 1 2 1A 2A 3A 4A 33 TX 21RX20M MALAYSIA...
Page 34: ...5 3 2 V Board 2 2 1A 2A 3A 4A 34 TX 21RX20M MALAYSIA...
Page 35: ...5 4 G Board 5 4 1 G Board 1 2 1A 2A 3A 4A 5A 6A 7A 8A 9A 35 TX 21RX20M MALAYSIA...
Page 36: ...5 4 2 G Board 2 2 1A 2A 3A 4A 5A 6A 7A 8A 9A 36 TX 21RX20M MALAYSIA...
Page 37: ...5 5 K Board 5 5 1 K Board 37 TX 21RX20M MALAYSIA...
Page 38: ...5 6 SW Board 5 6 1 SW Board 1 2 1A 2A 3A 38 TX 21RX20M MALAYSIA...
Page 39: ...5 6 2 SW Board 2 2 1A 2A 3A 39 TX 21RX20M MALAYSIA...
Page 40: ...6 Parts Locations 6 1 Packing Exploded View A 40 TX 21RX20M MALAYSIA...
Page 41: ...6 2 Packing Exploded View B 41 TX 21RX20M MALAYSIA...
