Dielectric Strength Test; Leakage Current Test - NEC MultiSync LCD1970NX Service Manual

4.3 Dielectric Strength Test

To confirm the freedom from insulation breakdown, testing should be carried out under the conditions
specified below.
1) Measuring conditions
• Measuring instrument:
• Testing point:
Note: The electrical circuit block means the power input block (primary side). Testing should be carried out
under the condition that both poles of the power plug are short-circuited. (Where a 3-core cord is
used, the two poles other than the earth terminal should be short-circuited.)
2) Judgment standard
The freedom from insulation breakdown should be confirmed under the condition that the applied
voltage is maintained at 1500V AC (+0 to 50V) for one minute.
Even though the result of this testing is OK, such a condition should be regarded as unacceptable if
there is a leakage (flashing) around the section where the test voltage has been applied.
If the result of insulation resistance test is found unacceptable, to be carried out after this testing, such a
condition should be regarded as that an insulation breakdown has occurred.

4.4 Leakage Current Test

A leakage current should be measured under the conditions specified below, in order to confirm that the
requirements of the judgment standard are met.
1) Measuring conditions
• Measuring instrument:
• Testing point:
• Condition of the set:
2) Judgment standard
The leakage current measured should be 1.5mA or less with an input of 240V AC × 1.06 +5/-0V (60Hz).
Dielectric strength tester (The specified voltage should be maintained in the
state that a current of 10mA is carried.)
Between the electrical circuit block and the exposed metallic block (D-SUB
connector)
Leakage current meter (A 1500Ω resistor should be incorporated,
together with a bypass capacitor of 0.15µF.)
Between the exposed metallic block (D-SUB connector) and Phases
A and B of the power source.
A power cable should be connected without connecting a signal generator.
The toggle switch on the set side should be turned ON and OFF.
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