DAEWOO ELECTRONICS 712D, Руководство по обслуживанию

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S AFETY PRECAUTIONS
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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.
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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.
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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.
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X-Ray
IMPORTANT SAFETY NOTICE: There are special components used in this analog color display, 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.
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.
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.
• Turn the Contrast & Brightness Control fully counterclockwise.
• 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.