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Laptop Screen Types and Repair Methods.

Sunday, December 21, 2014

In this article were going to disscuss Laptop Screen Types: (CCFL and LED discussion), and Repair Methods. Including LCD Bulb Replacement, Power Inverter Repair.

Laptop screens today will use one of two common lighting systems. Both are still considered LCD Screens because they are. The Image to the screen is Liquid Crystal Display; it is only the lighting that will change for these 2 types.

LED light on a laptop is newer technology because all screens used to use only CCFL bulbs. The CCFL bulb is a thin glass tube with a protruding metal pliable rod on either side. Wires are soldered to both ends of the bulb then attach to a plug that will plug into the power inverter… You will need to solder the wires to the ends if you ever need to order a replacement bulb. You can however usually find replacement bulbs that come prewired with plugs also attached. You get the same size bulb as your screen specs specify.

When disassembling the screen, you will start by removing the power inverter if it is attached. You will notice that all screens are framed with a thin metal frame. This helps to hold all the screen parts together it also helps by framing the front screen glass panel in and protects the glass edges from harm. You are going to use a Razor Blade here to help separate this metal frame from the rest of the screen.

This frame wraps from the front of the screen panel to the top of the panels edges all the way around the screen. Most screens will have 1 or several pieces of tape that cover the frames edge. You need to run the razor blade edge between the seam of the screen frame and the aluminum bulb backing plate. To do this you will flip the screen to its back side and start at the top of the screen, running the razor from right to left. Be very careful not to cut the LCD bulb wires or scratch any of the screen panels. The sides of the screen will usually have securing tape that you need to either peel away or carefully cut to separate the front metal frame.

Once you have cleared any securing tape, you will now be unsnapping the metal frame away from the screen panel. You will need a Plastic Pry Tool assist you in removing the frame. The best tool would a guitar pick. You need to start at the top. It is imperative that you do start at the top of the screen when removing the frame because you are not completely removing the frame (you can, but it is not needed to change a bulb).

You will wedge the pick in between the seam of the frame and screen panel top side. Slightly pry upward near one of the imprinted tabs on the frame and push outward away from the front of the screens glass panel. Do not force this frame away or you might crack the screen. Go Slow, Have Patience and you will easily be able to separate this frame… Slide the pick back and forth from the right side end of the frame to the left end side. Then you can do the same to the sides, though start from the top and work your way down the sides pushing the frame away while you are going… The frame will fall in front of the display panel (not literally ―fall‖). You can now, either, pull the frame away and set a side, or you can leave it attached to the bottom framing tape but just flip it down on the table while holding the screen up at a 90% angle.

You will now see an aluminum bulb guard on the rear upper side of the screen. This can sometimes have a micro sized screw on each side so look real close for one and remove it. Now, right where the screw you just removed was, flip the screen to the side and parallel with the bulb guard screw will be a screw on the side of the screen again it will be a micro sized screw and will need to be removed, the same goes for the opposite side of the screen, then again there might be a second screw on the side of the screen towards the bottom of the side. Some will have these and some will not.

The object now is to pull this metal bulb tray up and away from the screen to swap out the bulb. There will be a few things you will have to do before simply lifting this metal/aluminum tray away from the screen.

The red arrow shows the metal bulb tray and the blue arrow shows you will be sliding it outward to remove, after you free the LCD wires.

Remove any tape that is securing the LCD bulb plug wires to the screen bottom side (usually a piece of thin yellow tape). You should now see a white tab that the wires track through. This wire white tab/holder is attached to a thin plastic rail that runs horizontal along the top front of the screen and will be stuck to the screen using sticky double sided tape strips. What I do here is use a pry tool and gently lift up on the white small tab securing the wires… lift it up to a 90% angle and you will be able to pull each wire out of the track and away. One wire is short the other long. The long wire will be stuck to the thin horizontal plastic strip that runs along the top front of the screen, you simply will pull on the bulb wire to release it from the track along the front; it should peel right off. You should still have that small white plastic wire tab sticking up in the air (90%), and you will want to use that as a pull tab to pull the tab itself and the horizontal plastic bar away from the screen panel and metal bulb tray… The goal it to allow free space to slide the metal bulb guard out and away from the screen.

You will use a fingernail or a plastic pry tool to push the metal bulb tray upward, start on one side then slightly slide it a little bit, then go to the opposite side and slightly lift it, alternating until it is free from the screen. Be very careful when doing this otherwise the bulb will break (though it is already broke which is why you are changing it). Once you have the metal bulb guard free, set the screen aside. The bulb guard will have the bulb still inside its tray, there is actually a smaller metal tray inside the large metal tray, you can go ahead and separate these trays from one another now. Look at both ends of the LCD bulb… this is typically where a bulb failure will occur (at either end). Either the wire will overheat and will break, or it will deteriorate the wire to a very fragile state so that if you were to wiggle it slightly it would snap and break. Look at the very ends of the bulb too, a faulty bulb usually shows a blackish color at the end or both ends… this is due to internal bulb heat… which is why laptops can have color wash-outs (pinks, oranges, reds) to where the whole view of the screen when illuminated has a pastel transparent colored tint to it, the tint can change colors as well, and you can sometimes hear a faint buzzing noise from the bulb. Flickering of the light on and off is another signal that the bulb is failing.

Once again, look at the bulb ends (you should have only the smaller metal bulb guard and the bulb in front of you), there are white rubber caps on each side covering the LCD bulb power posts. These are there to keep the post and wire grounded so the screen doesn’t short the bulb. You do not want to lose these caps… they are not glued on, they only slide on, and can easily fall off, so be very cautious. You will use a plastic pick or pry tool now to push the actual LCD bulb out of the small metal tray/housing. Notice here the placement of the bulb wires at both ends, notice that they do not protrude straight out the back end of the bulb? No, they are bent to a right angle (90%) at the end of the bulb and are capped with the white rubber plug, they also bend towards the front of the metal tray, not the top, not downward… they do this for a reason… they do this to allow it to properly slide back into and out of the small metal tray/guard then slide back over the screens glass panel when reassembling so that the wires are both out of the way and ready to re-stick along the top front plastic rail.

So, when replacing the bulb, you will make sure the ends are properly recapped with the white grounding rubber caps and that the wires are placed facing the correct direction for reassembly. If you need to, take photos while you work to be able to remember assembly and reverse process.

The Power inverter is the only part left for screen repairing.

You can only do so much to repair the inverter if failure occurs. The only thing I have found that works about %60 of the time is to change the transformer block on the Inverter. It is the part with the copper wire wrapped all around it… a long 
rectangular shaped component with legs on both ends (usually 2 to 3 on one side and 2 to 6 on the other – the legs attaching to contact pads on the inverter board. You will need to use a soldering gun and flux paste.

To replace a cracked screen (or what ever the issue…) you can order the screen by the model number of the laptop, but I do not recommend doing so and it is the Lazy way to replace it.

Not only is it not correct, it could harm the laptop by possibly installing an incompatible screen. You need to realize here that not all screen vendors will send the exact screen you need and will sometimes replace with the closest compatible screen, even swapping stickers/labels… I’ve seen it all…

The way you should be replacing / ordering the screen is to remove the screen, then look at the white large sticker on the rear side of the screen. It will tell you the exact part number of the screen, it will also show you the type/model of screen. These numbers/letters are important in ensuring you receive an exact replacement part.

The replacement screen part replacement number will almost always include the screens size in the number.

Here is a typical screen part order number: LP173WD1 HD+ (TL) (A2) 17.3”

Notice in the number that the screen size is in it (LP173), you will find this in most all screen numbers. Now, notice the (TL) and the (A2)… this is very important that you replace with the same exact numbers. If you don’t, you are risking damaging the laptop, or the screen simply will not work, it will show grey color or a white-out.

Laptop Screen Disassembly Instructions

Most screens can be disassembled without removing them from the bottom base, but some models will not allow removal of the front bezel without first removing the screen away from the base. To start the disassembly, you will need to remove any retaining screws on the front frame/bezel which are typically located on all 4 corners of the screen and some in the upper and lower center area of the frame. A lot of the newer laptops will have fewer screws used and more snaps. They will also use flat – hidden screw covers that are thick sticker tab covers and not the typical rubber shoe screw cover. Use a razor blade or extremely thin plastic tool to pry the screw covers away from the bezel making sure not to scratch the bezel or not to ruin the screw cover. Once all the screws are removed, (2 to 8), you can remove the front bezel from the rear lid.

This does not just lift right off now… it will be snapped onto the rear panel and you will need to un-snap all the locking tabs all the way around the screen.

You will start this process using a guitar pick or similar tool and start at the upper right corner of the screen. Wedge the pick between the bezel and the rear panel and pry towards the front – prying away from each other, you will eventually unsnap the nearest snapping tab then continue around the lid. I have found it easier if you slightly bend the area you are unsnapping inward toward the center of the screen and the locking panel tab will release easier.

When you get to the bottom of the screen front bezel it can sometimes be tricky to remove this area. This area will sometimes also have double sided tape securing the 2 pieces (front and back) together, and you will need to pull on the bottom bezel piece while lifting in an upward motion to release the piece. The way I do it is I will loosen the top of the bezel, then, I will go down each side. When I have the top and sides all unsnapped, I will pull outward (towards yourself) on the screens front bezel, and doing this will help me see what I need to do to remove/release the lower portion of the screen front bezel. Take a look at the hinge area, some laptops are built so that the front bezel curves around and under the hinge, so if you are removing the bezel without first removing the screen and hinges, you will have to bend the bezel outward and then upward to pull it away from the hinges. It is a bit tricky but with practice it gets easy.

Continuing on… Upon pulling the top and sides outward, I will insert my finger (you can use a pry tool or pick) in between the screen and the front bezel bottom portion of the frame… Then I will slide my finger across from right to left while pulling outward slightly, this should ―pop‖ the tabs and it will pull the 2 pieces apart if they are being secured with any double sided tape strips.

Note here that with some front bezels, you will need to gently pull upward while at the same time ―popping‖ the tab by wedging the pick between the screen and bezel and prying outward…

Note that Front Bezels/Frames do not have any attached wires or cables. Also note that certain models like DELL will have a hinge extension piece that extends into the hinge cover. So if you are removing the bezel without first removing the screen away from the laptop, you will need to pull this extension piece out of the hinge area, do this carefully but you will be able to with some patience…

Hopefully you have removed the front bezel, I will now move on.

You should have the screen in front of you, the hinges and hinge rails should still be connected. You will first want to remove the retaining screws that secure the screen side rails to the screen. These side rails are almost always directly connected to the hinges. Typically there are 2 to 4 screws on both sides of the screen, magnetize your Micro sized Phillips head screwdriver and remove all screws on both sides of the screen, set aside.

Make Sure you separate your Upper Half Screen Parts from your Lower Half Parts, this includes all screws and covers.

Some hinge rails will also have screws at the top that you will be removing and on the bottom you will remove to allow the screen to be removed. I will typically leave the bottom screws – securing the hinge to the lid – unscrewed, and I will pull the screen away from the rear lid (the only tricky part doing it this way is the bottom – side rail screw, it can be difficult to remove this one without loosening or removing the bottom hinge screws).

Now, before you pull the screen from the rear lid, unplug the Webcam (if applicable), and unplug the CCFL bulb wires/plug from the power inverter. If able to, unplug the display cable wire set that runs to the power inverter.

Grab the top center of the Display Screen and pull it forward to lie it flat (face down) in front of the lid. Note that this screen will rest on the palm rest if you are doing this without removing the screen from the laptop bottom base…

You have the screen face down so that you can detach the display cable from the rear side of the screen. All Display cables will have a piece of Pull Tab Tape attached to them. Some will be fully secured to the screen rear side and some will have an area at the tip of the tab tape that isn’t sticky allowing you to grab and peel the adhesive part free… then you will use that tab tape to pull the display cable free from its port in the rear panel. Some display cables will also have a rectangular metal wire pull tab with a blue, white or black plastic pull tab attached. You will do the same with these and grab the end tab pulling it downward to release the display cable from the plug port.

Some cables will also have locking tabs on the left and right side. To release the cable, you will need to depress both the left and right sides simultaneously while pulling the cable flat away not upward…

Assuming you already unplugged the power inverter, set the screen aside and you will have completed the screen disassembly. Any remaining parts will stay in place.

Some screens will also have secondary horizontal support rails, remember their position when reassembling and do not forget to reinstall them.

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