Safety Precautions - Acer AL718 Service Manual

SAFETY PRECAUTIONS

1. CAUTION:
No modification of any circuit should be attempted.
Service work should only be performed after you
are throughly familiar with all of the following safety
checks and servicing guide lines.
2. SAFETY CHECK
Care should be taken while servicing this LCD
display. Because of the high voltage used in the
inverter circuit. These voltage are exposed in such
areas as the associated transfomer circuits.
3. POWER SUPPLY REQUIREMENTS
The external powr converter for this display
utilizes AC and DC cords ,
detachable , but DC cord is permanently
attached . Any attempt to
adapter could result in serious problem on the
display.
4. LEAKAGE CURRENT HOT CHECK
4-1 Plug the AC cord directly into the AC outlet.
Do not use an isolation transformer during this
check.
4-2 Connect a 1500 ohm , 10 watt resistor ,
paralleled by a 0.15uF capacitor between each
metallic part and a good earth ground.
4-3 Use an AC voltmeter with 1000 ohm / volt or
more sensitivity and measure the AC voltage
across the combination 1500 ohm resistor
and 0.15uF capacitor.
4-4 Move the resistor connection to each exposed
metallic part and measure the voltage.
4-5 Reverse the polarity of the AC plug in the AC
outlet and repeat the above measurement.
AL718
AC cord is
replace another
4-6 Voltage measured must not exceed 1.5 vol
RMS, from any exposed metallic part to th
ground. A leakage current tester may be
used in the above hot check, in which case
any circuit measured must not exceed 1.0
miliamp. In the case of a measurement
exceeding the 1.0 miliamp value, a rework i
required to eliminate the chance of a shock
hazard.
AC VOLTMETER
To Metal Parts 1500
V
0.15u
.
10W Earth Ground
B-1