Panasonic PT-52DL52, Service Manual

Page: 5 / 189

3. Use a high impedance AC voltage meter to measure the voltage
across the resistor.
4. Measure the voltage at each exposed metallic part.
5. Reverse the AC plug inserting direction at the AC line outlet and
repeat each of the above measurements.
6. The voltage at any point must be less than 0.25Vrms.
7. A leakage current tester (SIMPSON MODEL 228 or the equivalent)
may be used to make the hot checks. In this case, the current must
be less than 500 A.
8. If the reading is more than the above value, the set must be
repaired and rechecked before it is returned to the customer
because of a possibility of an electrical shock.
1.4. Hot-Check Circuit
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
Performance
Voltmeter
(rms reading)
Accuracy: 2%
Input resistance: 1M
Input capacitance: 200pF
Frequency range: 15Hz to 1MHz
1.5. Lamp Precautions
- Be sure to unplug the power cord from the power outlet when
replacing the lamp.
- Because the lamp reaches a very high temperature during its
5