AOC 25G4SRE (01) PDF Document

When servicing your AOC 25G4SRE, observe the original lead dress. If a short circuit is found, replace all parts that have been overheated or damaged. After servicing, ensure that all protective devices such as insulation barriers and insulation paper shields are properly installed. Also, perform the following leakage current checks to prevent exposure to shock hazards:

1) Leakage Current Cold Check

2) Leakage Current Hot Check

3) Prevention of Electro Static Discharge (ESD) to Electrostatically Sensitive components.

Follow regulations and warnings: It is crucial to identify potential hazards or risks for service personnel when opening and disassembling the unit, such as avoiding electrical shock from a live power supply or charged parts.

Be careful of electrical shock: To prevent damage that might result in electric shock or fire, do not expose the monitor to rain or excessive moisture. The monitor must not be exposed to dripping or splashing water, and objects filled with liquid, such as vases, must not be placed on top of it.

Electro static discharge (ESD): Some semiconductor devices can be easily damaged by static electricity. These components are known as Electrostatically Sensitive (ES) Devices. Use appropriate techniques to reduce component damage caused by ESD.

About lead-free solder (PbF): This product is manufactured using lead-free solder. Lead-free solder must be used in the servicing and repairing of this product.

Use specified parts: Special parts for fire retardancy (resistors), high-quality sound (capacitors), and low noise (resistors) are used. When replacing any components, be sure to use only the manufacturer’s specified parts shown in the parts list.

1. Always unplug the receiver AC power cord from the AC power source before:

a. Removing or reinstalling any component, circuit board module or any other receiver assembly.

b. Disconnecting or reconnecting any receiver electrical plug or other electrical connection.

c. Connecting a test substitute in parallel with an electrolytic capacitor in the receiver.

CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explosion hazard.

2. Test high voltage only by measuring it with an appropriate high voltage meter or other voltage measuring device (DVM, FETVOM, etc) equipped with a suitable high voltage probe. Do not test high voltage by “drawing an arc”.

3. Do not spray chemicals on or near this receiver or any of its assemblies.

4. Do not defeat any plug/socket B+ voltage interlocks.

5. Do not apply AC power to this instrument.

6. Always connect the test receiver ground lead to the receiver chassis ground before connecting the test receiver positive lead. Always remove the test receiver ground lead last. Capacitors may result in an explosion hazard.

7. Use with this receiver only the test fixtures specified in this service manual.

CAUTION: Do not connect the test fixture ground strap to any heat sink in this receiver.

8. Insulation resistance between the cord plug terminals and the external exposure metal should be more than Mohm by using the 500V insulation resistance meter.

1. Immediately before handling any semiconductor component or assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, wear a commercially available discharging wrist strap device.

2. After removing an electrical assembly equipped with ES devices, place it on a conductive surface, such as aluminum foil, to prevent electrostatic charge buildup.

3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.

4. Use only an anti-static type solder removal device.

5. Do not use freon-propelled chemicals as they can generate electrical charges.

6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it.

7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed.

CAUTION: Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged replacement ES devices. Harmless motions like brushing clothes together can generate enough static electricity to damage an ES device.

Note: A “note” provides information that is not indispensable, but may nevertheless be valuable to the reader, such as tips and tricks.

Caution: A “caution” is used when there is danger that the reader, through incorrect manipulation, may damage equipment, lose data, get an unexpected result or has to restart (part of) a procedure.

Warning: A “warning” is used when there is danger of personal injury.

Reference: A “reference” guides the reader to other places in the manual where they will find additional information on a specific topic.

Philips-head Screwdriver: Use to fasten/remove the K- or B-typed screws.

Gloves: To protect the LCD Panel and your hand.

C/D Disassembly Tool: Use to open the cosmetic cover and avoid scratches.

Spacer Screwdriver: Use to fasten/remove spacer screws or hex screws.

1. Remove stand and base.

2. Remove the screws from the rear of the monitor.

3. Use a disassembly tool to open all the latches along the edge of the rear cover.

4. Disconnect the connector revealed after separating the covers.

5. Remove the rear cover, then take off all of the tapes and disconnect the internal connectors.

6. Remove the screws securing the internal components.

7. Remove the Mylar sheet.

8. Remove screws to get the main board and power board.

9. Take off all of the tape and disconnect the panel connector.

10. Remove the nuts and deco bezel to access and remove the panel.