Panasonic DMC-TZ80EB, Service Manual

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3
1 Safety Precautions
1.1. 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 Replacement Parts List. It is
essential that these critical parts should be replaced with
manufacturer's specified parts to prevent X-RADIATION,
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 AC Adaptor 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 personal injury from electrical
shocks. It will also protect AC Adaptor from being
damaged by accidental shorting that may occur during
servicing.
3. When servicing, observe the original lead dress. It 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.
1.2. 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

and 5.2M

. When the
exposed metal does not have a return path to the chassis,
the reading must be infinity.
1.3. 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

, 10 W resistor, in parallel with a 0.15

F
capacitor, between each exposed metallic part on the set
and a good earth ground, as shown in Figure 1.
3. Use an AC voltmeter, with 1 k

/V 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 V 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 mA. 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.
Figure 1