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1 SAFETY PRECAUTIONS
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GENERAL GUIDELINES
1. IMPORTANT SAFETY NOTICE
There are special components used in this equipment which are important for safety. These
parts are marked by
in the Schematic Diagrams, Circuit Board Layout, Exploded Views and
ReplacementParts List. It is essential that these critical parts should be replaced with
manufacturer´s specified parts to prevent shock, fire or other hazards. Do not modify the
original design without permission of manufacturer.
2. An Isolation Transformer should always be used during the servicing of VCR whose chassis is
not isolated from the AC power line. Use a transformer of adequate power rating as this
protects the technician from accidents resulting in personalinjury from electrical shocks. It will
also protect VCR from being damaged by accidental shorting that may occur during servicing.
3. 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.
4. After servicing, see to it that all the protective devices such as insulation barriers, insulation
papers shields are properly installed.
5. After servicing, make the following leakage current checks to prevent the customer from being
exposed to shock hazards.
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 thechassis, the reading should be
between 1M ohm and 5.2M ohm. When the exposed metal does not have a return path to the
chassis, the reading must be infinity.
Figure 1
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