Panasonic PT-D7700E, Service Manual

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1 Safety Precautions
1.1. General Guidelines
· For continued safety, no modification of any circuit must be
attempted.
·
Unplug the power cord from the power outlet before
disassembling this projector.
·
It is advisable to use an isolation transformer in the AC
power line before the service.
· Observe the original lead dress during the service. If a short
circuit is found, replace all the parts overheated or
damaged by the short circuit.
·
After the service, all the protective devices such as
insulation barriers, insulation papers, shields, and isolation
R-C combinations must be properly installed.
·
After the service, check the leakage current to prevent the
customer from getting an electric shock.
1.2. Leakage Current Check
1. Prepare the measuring circuit as shown in Fig.1.
Be sure to use a voltmeter having the performance
described in Table 1.
Fig. 1
Table 1
Fig. 2
2. Assemble the circuit as shown in Fig. 2. Plug the power
cord in a power outlet.
3. Connect M1 to T1 according to Fig. 2 and measure the
voltage.
4. Change the connection of M1 from T1 to T2 and measure
the voltage again.
5. The voltmeter must read 0.375 V or lower in both of steps
3 and 4. This means that the current must be 0.75 mA or
less.
6. If the reading is out of the above standard, the projector
must be repaired and rechecked before returning to the
customer because of a possibility of an electric shock.
5
PT-D7700U / PT-D7700E