Precautions And Safety Notices - ViewSonic E70FSB-2 - E 70F+SB - 17" CRT Display Service Manual

1. Precautions And Safety Notices

This service information is designed for experience repair technicians only and is not designed for use by the general public.
It does not contain warnings or cautions to advise 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 lines.
2. SAFETY CHECK
Care should be taken while servicing this CRT display because of the high voltage used in the deflection circuits.
These voltages are exposed in such areas as the associated flyback and yoke circuits.
3. FIRE & SHOCK HAZARD
3-1 Insert an isolation transformer between the CRT display and AC power line before servicing the chassis.
3-2 In servicing pay attention to original lead dress especially in the high voltage circuit. If a short circuit is found,
replace all parts which have been overheated as a result of the short circuit .
3-3 All the protective devices munt be reinstalled per original design.
3-4 Soldering must be inspected for possible cold solder joints, frayed leads, damaged insulation, solder splashes or
sharp solder points. Be certain to remove all foreign material.
4. LEAKAGE CURRENT COLD CHECK
4-1 Unplug the AC cord and connect a jumper between the two prongs on the plug.
4-2 Turn the CRT display power switch "on".
4-3 Measure the resistance value with an ohmmeter between the jumpered AC plug and each exposed metallic part
on the CRT display such as the metal frame, screwheads, control shafts, etc. When the exposed metallic part has
a return path to the chassis, the reading should be 1.8 megohm minimum .
5. LEAKAGE CURRENT HOT CHECK
5-1 Plug the AC cord directly into the AC outlet. Do not use an isolation transformer during this check.
5-2 Connect a 1500 ohm, 10 watt resistor, paralleled by a 0.15uF capacitor between each exposed metallic part and
a good earth ground (as shown in Fig.1).
5-3 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.
ViewSonic Corporation
WARNING!
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