2.1.1. Leakage Current Cold Check
1. Unplug the AC cord and connect a jumper between the two
prongs on the plug.
2. Measure the resistance value, with an ohmmeter, between
the jumpered AC plug and each exposed metallic cabinet
part on the equipment such as screwheads, connectors,
control shafts, etc. When the exposed metallic part has a
return path to the chassis, the reading should be between
1M
W
and 5.2M
W
.
When the exposed metal does not have a return path to the
chassis, the reading must be
.
Figure 1
2.1.2. Leakage Current Hot Check (See
Figure 1.)
1. Plug the AC cord directly into the AC outlet. Do not use an
isolation transformer for this check.
2. Connect a 1.5k
W
, 10 watts resistor, in parallel with a 0.15µF
capacitors, 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 an AC voltmeter, with 1000 ohms/volt or more
sensitivity, to measure the potential across the resistor.
4. Check each exposed metallic part, and measure the
voltage at each point.
5. Reverse the AC plug in the AC outlet and repeat each of the
above measurements.
6. The potential at any point should not exceed 0.75 volts
RMS. A leakage current tester (Simpson Model 229 or
equivalent) may be used to make the hot checks, leakage
current must not exceed 1/2 milliamp. In case a
measurement is outside 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.
1 Applicable signals
2 Safety Precautions
2.1. General Guidelines
1. 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.
2. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly
installed.
3. After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.
5
TH-42PA50A / TH-42PA50H / TH-42PA50M / TH-37PA50H / TH-37PA50M
Summary of Contents for TH-37PA50H
Page 17: ...7 2 Lead of Wiring 2 17 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 18: ...7 3 Lead of Wiring 3 18 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 21: ...8 3 No Picture 21 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 24: ...24 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 25: ...9 3 Option Description 25 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 26: ...26 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 64: ...TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M 64 ...
Page 126: ...TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M 126 ...
Page 128: ...15 2 Packing Exploded Views 1 128 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 129: ...15 3 Packing Exploded Views 2 129 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
Page 130: ...15 4 Packing Exploded Views 3 130 TH 42PA50A TH 42PA50H TH 42PA50M TH 37PA50H TH 37PA50M ...
