Disassembling Lg Lcd Monitors: A Step-By-Step Guide

If you're looking to tear down and repair your LG LCD monitor, you've come to the right place. In this guide, we'll walk you through the process of disassembling your monitor, identifying and fixing common issues, and putting it back together. We'll also explore some of the potential challenges and provide tips to make the process smoother. Whether you're experiencing issues with your monitor or simply curious about its inner workings, read on to learn more about disassembling your LG LCD monitor.

Characteristics of Disassembling an LG LCD Monitor

Getting the bezel off

If you are lucky, the snaps will come apart, but the corners are the most difficult. Three perpendicular planes meet together, making the enclosure much stiffer near them. There may be around 20 snaps around the bezel, and the majority of breaks will be in the corners.

Aside from its cosmetic function, the bezel also hosts part of the power button, the snap holes for the bottom trim, and structural reinforcements around the snap notches to ensure the LCD does not accidentally fall off. Breaking too many of these will force you to use duct tape for reassembly.

With the front bezel out of the way, flip the chassis and the panel will simply fall out. If you take an LCD apart, remember to support it adequately as you lift the rear cover up. Also, keep an eye out for any cables that might require unplugging, such as the audio and button harness.

Removing the LCD panel

If you are lucky, the snaps will come apart without too much trouble. However, the corners are the most difficult part, as three perpendicular planes meet together, making the enclosure much stiffer near them. Take your time and be gentle to avoid breaking the snaps. Once all the snaps are undone, carefully flip the chassis, and the LCD panel will come loose. It is important to support it adequately as you lift the rear cover, and keep an eye out for any cables that might need unplugging, such as the audio and button harness.

With the LCD panel removed, you will be left with a mostly bare housing, containing only the buttons, power switch, and audio jack PCBs. The panel accounts for about half of the screen's total weight, so be prepared for the chassis to feel very light. Take care when handling the LCD panel, as it is fragile and can be easily damaged.

At this point, you will have successfully removed the LCD panel from your LG LCD monitor. From here, you can proceed to disassemble other components or perform any necessary repairs. Remember to keep track of the various parts and screws removed during the process to facilitate easier reassembly.

Unplugging cables

Before you begin, make sure the monitor is switched off and unplugged from the power source. This is an essential safety precaution to prevent any electrical hazards.

The first step is to carefully remove the bezel, which is the outer frame of the monitor. This part requires patience and a gentle touch to avoid breaking any snaps or causing cosmetic damage. Use a soft plastic tool, such as a reward card, to gently pry the bezel away from the LCD panel. Start from one corner and slowly work your way around the perimeter. Be extra cautious when dealing with the corners, as three perpendicular planes meet there, making it a stiffer area. Once you have successfully removed the bezel, set it aside safely.

With the bezel removed, you will now have access to the internal components of the monitor. Identify the cables that need to be unplugged. These may include the audio and button harness cables. Carefully disconnect these cables from their respective ports or connectors. It is important to do this gently to avoid any damage to the cables or the connectors.

Some cables may be secured with metalized tape or other types of fasteners. If you encounter such cables, carefully remove the tape or fasteners before attempting to unplug the cables. Make sure to note how the cables are routed and secured so that you can properly reconnect them during the reassembly process.

After all, the cables have been successfully unplugged; place them aside in a safe location, ensuring they do not get tangled or damaged during the rest of the disassembly process.

By following these steps, you will have safely and effectively unplugged the cables during the disassembly of your LG LCD monitor. Remember to take your time and be gentle to avoid any damage to the cables or other components.

Disassembling the electronics bay

The bezel is the trickiest part of the disassembly process. The bezel's snaps prevent the LCD panel from falling out of its enclosure, so you must be careful not to break them. Use a soft plastic card, such as a rewards card, to gently pry the hooks off. Start by prying the bezel off at the corners, as this is where the enclosure is stiffest. There are 20 snaps around the bezel, and the corners are the most challenging to detach. Once you have successfully removed the bezel, set it aside.

With the bezel out of the way, you can now access the LCD panel. Flip the chassis, and the panel will come loose. Remember to support the LCD adequately when lifting it out, and be careful not to damage any cables. You may need to unplug some cables, such as the audio and button harness.

After removing the LCD, you will be left with a mostly bare housing. The remaining components include the buttons, power switch, and audio jack PCBs. These can be carefully detached from the housing. The power switch PCB, for example, is a simple package of one switch and a dual-LED (amber and blue).

The electronics tray, a steel tray that holds the display controller interface, power supply, and CCFL inverters, is attached to the back of the LCD with metalized tape. Carefully detach the electronics tray from the LCD, being mindful of any cables or connections that may still be attached.

Repairing the capacitors

Before beginning any repairs, make sure to disconnect the power supply by unplugging the monitor or removing the battery. This will reduce the chance of an electric shock. Additionally, it is important to be aware of the dangers associated with handling capacitors, as they may hold a major charge even when disconnected from the power source. Unless you have significant electronics repair experience, it may be best to take your monitor to a professional repair service.

If you choose to proceed with repairing the capacitors yourself, here are the steps you can follow:

Step 1: Remove the Case

Unscrew the plastic case at each corner or wherever you see screws holding the back and front frames together. You can use a thin, flexible tool like a plastic putty knife to gently pry apart the case. Be careful not to use a metal object as it may destroy the components by chipping or causing an electrical short.

Step 2: Locate the Power Supply Board

The power supply board is usually located near the power socket. You may need to unscrew additional panels to find it. This board will have several cylindrical capacitors, including one large one. However, these capacitors may be on the other side of the board and not visible until you finish disconnecting it.

Step 3: Disconnect the Circuit Board

Remove all screws and ribbon cables holding the circuit board in place. When disconnecting a cable, always pull directly out of the socket. Pulling a ribbon cable vertically when it is in a horizontal socket can easily break it. Some ribbon cables have a small tab that you can pull to disconnect them.

Step 4: Locate and Discharge the Largest Capacitors

Carefully lift the board by the edges, without touching any metal pins or attached components. On the other side of the board, you will find the cylindrical capacitors. Each capacitor is attached to the board with two pins. To reduce the risk of electric shock, you can discharge the stored electricity using a resistor in the range of 1.8-2.2kΩ and 5-10 watts. Put on rubber gloves and touch the two resistor leads to the pins of the largest capacitor for several seconds. Repeat this process for each of the largest capacitors.

Step 5: Identify and Photograph Broken Capacitors

Look for capacitors with domed or bulging tops, leaking fluid, or a crusty buildup of dried fluid. Before removing any capacitors, be sure to photograph or record their positions and the markings on their sides. It is crucial to know which pin attaches to the negative and positive sides of each capacitor. If you are removing more than one type of capacitor, ensure you know where each one goes. If none of the capacitors appear damaged, you can test each one with a multimeter set to resistance.

Step 6: Desolder Broken Capacitors

Use a soldering iron and desoldering pump to remove the pins connecting the faulty capacitors. Set aside the broken capacitors.

Step 7: Purchase Replacements

You can find replacement capacitors at any electronics supply store. Look for capacitors with the following attributes:

• Size: Identical to the old capacitor
• Voltage (V, WV, or WVDC): Equal to or slightly higher than the old capacitor
• Capacitance (F or µF): Equal to the old capacitor

Step 8: Solder the New Capacitors

Use your soldering iron to attach the new capacitors to the circuit board, ensuring that the negative (striped) side of each capacitor is connected to the same pin as the old capacitor. Check that all new connections are solid.

Step 9: Reassemble and Test

Reattach all cables, panels, and components exactly as they were before. You may test the monitor before screwing in the final plastic panel, as long as all other parts are connected. If it still doesn't work, you may need to consult a professional or consider buying a replacement.

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