Safety Precautions - Daewoo 719B Service Manual

SAFETY PRECAUTIONS

CAUTION: No modifications of any circuits should be attempted. Service work should be performed
only after you are thoroughly familiar with all of the following safety checks and servicing
guidelines.
Safety Check
Care should be taken while servicing this analog color display because of the high voltages used in the
deflection circuits. These voltages are exposed in such areas as the associated flyback and yoke circuits.
Fire & Shock Hazard
• Insert an isolation transformer between the analog color display and AC power line before servicing the
chassis.
• When servicing, pay close attention to the original lead dress especially in the high voltage circuit area;
if a short circuit is found, replace all parts which have been overheated as a result of the short circuit.
• All the protective devices must be reinstalled per original design.
• Soldering must be inspected for possible cold solder points, frayed leads, damaged insulation, solder
splashes or sharp solder points. Be certain to remove all foreign materials.
Implosion Protection
Picture tube in this monitor employs intergral implosion protection system, but care should be taken to
avoid damage and scratching during installation.
Only use same type replacement picture tubes.
IMPORTANT SAFETY NOTICE: There are special components used in this analog color display,
X-Ray
WARNING: The only potential source of X-Ray is the picture tube. However when the high voltage
circuitry is operating properly, there is no possibility of an X-Ray problem. The basic
precaution which must be exercised is to keep the high voltage at the following factory
recommended level.
NOTE: It is important to use an accurate, periodically, calibrated high voltage meter.
• To measure the high voltage, use a high-impedance high-voltage meter.
Connect(-) to chassis and (+) to the CRT anode button.
• Set the Contrast & Brightness Control to the minimum on OSD Menu.
• Measure the high voltage. The high voltage meter should indicate the following factory
recommended levels.
• If the upper meter indication exceeds the maximum level, immediate service is required to
prevent the possibility of premature component failure.
• To prevent X-Ray possibility, it is essential to use the specified picture tube.
• The normal high voltage is 25.5KV or below and must not exceed 29KV at zero beam current
at rated voltage.
which are important for safety. These parts are shaded on the
schematic diagram and on the replacement parts list. It is essential
that these critical parts should be replaced with manufacturer's
specified parts to prevent X-Ray, shock, fire or other hazards. Do
not modify the original design without getting written permission
from DAEWOO ELECTRONICS CO. or this will void the original
parts and labor warranty.
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