Precautions And Safety Notices - ViewSonic VE710b-1 Service Manual

1. Precaution & Safety Notice
This service information designed for experienced repair technicians only and is not designed for use by the
general public.
It does not contain warnings or cautions to avoid non-technical individuals of potential dangers in
attempting to service a product.
Products powered by electricity should be serviced or repaired only by experienced professional technicians.
Any attempt to service or repair the product or products dealt within this service information by anyone else
could result in serious injury or death.
1. Caution :
No modification of any circuit should be attempted . Service work should only be performed after you are
thoroughly familiar with all of the following safety checks and servicing guide line.
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 transformer circuits .
3. LEAKAGE CURRENT HOT CHECK
3 -1 Plug the AC cord directly into the AC outlet. Do not use an isolation transformer during this check.
3-2 Connect a 1500 ohm , 10 watt resistor , paralleled by a 0.15uF capacitor between each metallic part and a good
earth ground.
3-3 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.
3-4 Move the resistor connection to each exposed metallic part and measure the voltage.
3-5 Reverse the polarity of the AC plug in the AC outlet and repeat the above measurement.
3-6 Voltage measured must not exceed 1.5 volt RMS, from any exposed metallic part to the ground. A leakage
current tester may be used in the above hot check, in which case any circuit measured must not exceed 1.0
milliamp. In the case of a measurement exceeding the 1.0 milliamp value, a rework is required to eliminate the
chance of a shock hazard .
ViewSonic Corporation
WARNING!
AC VOLTMETER
V
0.15u
.
To Metal Parts 1500 10W Earth Ground
Confidential - Do Not Copy
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VE710b/s-1