1.1.2. Leakage Current Hot Check
1 Safety Precautions
1.1. 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, ensure that all the protective devices such as insulation barriers, insulation papers shields are properly installed.
3. After servicing, check for leakage current checks to prevent from being exposed to shock hazards.
1.1.1. Leakage Current Cold Check
1. Unplug the AC cord and connect a jumper between the two prongs on the plug.
2. Using an ohmmeter measure the resistance value, 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
Ω
and 5.2
Ω
.
When the exposed metal does not have a return path to the chassis, the reading must be
.
1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.
2. Connect a 1.5k
Ω
, 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. should the measurement is outside of the limits
specified, there is a possibility of a shock hazard, and the equipment should be repaired and re-checked before it is returned
to the customer.
Fig. 1
3
SC-EN38GCS
Содержание SC-EN38GCS
Страница 10: ...7 Operation Procedures 7 1 Main Unit Remote Control Key Buttons Operation 10 SC EN38GCS ...
Страница 11: ...7 2 Attach the stand to the unit 7 3 Connection 11 SC EN38GCS ...
Страница 12: ...7 4 External unit 12 SC EN38GCS ...
Страница 13: ...7 5 Disc Information 13 SC EN38GCS ...
Страница 21: ...9 2 2 For Speaker unit SB EN38 9 3 Main Parts Location Diagram 21 SC EN38GCS ...
Страница 58: ...58 SC EN38GCS ...
Страница 60: ...SC EN38GCS 60 ...
Страница 66: ...66 SC EN38GCS ...
Страница 76: ...SC EN38GCS 76 ...
Страница 85: ...20 Exploded Views 20 1 Cabinet Parts Location SC EN38GCS 85 ...
Страница 86: ...SC EN38GCS 86 ...
Страница 87: ...20 2 Packaging SC EN38GCS 87 ...
Страница 88: ...SC EN38GCS 88 ...