File name SyncMaster 753DFX76DF753V753S76V76E Chassis AN17K AN17L AN17KS.PDF
Chassis AN17K* AN17L* Model 753DFX, 76DF 753v, 753s 76V, 76E
1. Precautions 2. Product Specifications 3. Disassembly & Reassembly 4. Alignment & Adjustments 5. Troubleshooting 6. Exploded View & Parts List
7. Electrical Parts List 8. Block Diagram 9. Wiring Diagram 10. Schematic Diagrams
1-1 Safety Precautions
WARNINGS 1. For continued safety, do not attempt to modify the circuit board. 2. 3. Disconnect the AC power before servicing. When the chassis is operating, semiconductor heatsinks are potential shock hazards. 3. 2. Inspect all protective devices such as nonmetallic control knobs, insulating materials, cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacitor networks, mechanical insulators, etc. Leakage Current Hot Check (Figure 1-1): WARNING: Do not use an isolation transformer during this test. Use a leakage current tester or a metering system that complies with American National Standards Institute (ANSI C101.1, Leakage Current for Appliances), and Underwriters Laboratories (UL Publication UL1410, 59.7). With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. With the unit's AC switch first in the ON position and then OFF, measure the current between a known earth ground (metal water pipe, conduit, etc.) and all exposed metal parts, including: metal cabinets, screwheads and control shafts. The current measured should not exceed 0.5 milliamp. Reverse the power-plug prongs in the AC outlet and repeat the test.
(READING SHOULD NOT BE ABOVE 0.5mA)
Servicing the High Voltage and CRT :
WARNING: A high voltage VR replaced in the wrong direction may cause excessive X-ray emissions. 1. When servicing the high voltage system, remove the static charge by connecting a 10 kohm resistor in series with an insulated wire (such as a test probe) between the chassis and the anode lead. When troubleshooting a monitor with excess HV, avoid being unnecessarily close to the monitor. Do not operate the monitor for longer than is necessary to locate the cause of excessive voltage. High voltage should always be kept at the rated value (not higher). Only when high voltage is excessive are X-rays capable of penetrating the shell of the CRT, including the lead in glass material. Operation at high voltages may also cause failure of the CRT or high voltage circuitry. When the HV regulator is operating properly, there is no possibility of an X-ray problem. Make sure the HV does not exceed its specified value and that it is regulating correctly. The CRT is especially designed to prohibit X-ray emissions. To ensure continued X-ray protection, replace the CRT only with one that is the same or equivalent type as the original. Handle the CRT only when wearing shatterproof goggles and after completely discharging the high voltage anode. Do not lift the CRT by the neck.