A common fault with LCD monitors.

Jan 9, 2007
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This fault I have seen with many LCD monitors. It starts with a black screen.
If you were to shine a torch or a lamp on the screen and with a good eye you can just see an image. The fault is with the lamps. In fact it is caused by a
wire burning off one of the lamps, but you need to pull the unit totally apart
to fix this.
If you were to take to a repairer they would write it off or request that you need the LCD pannel to be replaced at cost more than what the unit is worth. This is because the lamps and the LCD pannel are one complete unit, however if you are very careful and have clean dust free envioronment this fault can be fixed.
First you have to pull the unit a part of course, and there are many screws and plastic clips if you are carefull this can be overcome.
Just like installing mother boards. you need the same proceedure to remove the electronics, with anti static proceedures, place the electronics in those anti static bags of wrap them up in aluminium foil.
You need to be very carefull in removing the ribbon connectors from the driver PCB to the pannel. To release these connectors you need a jewlers screw driver as there is a small plastic clamp that needs to pushed forward and up, be carefull with these they can be easly broken.
Remove the backing chassis and front panel buttons from escutchion.
Put all you packaged electronics in a box and screws in sealed container, nothing worse these searching the floor and work bench for 3mm screws.
Carefully and I mean carefully remove LCD panel from escutchion.

Pulling apart the LCD pannel.

More screws and metal tabs which need to be bent back.
The backing pannel although metal is very tightly fitted and the ribbon connectors can get in the way of removal and assembly just be aware.
Once you have removed the backing panel you will see the optical panel, which is white you need to take this out, as this is the component you need to fix. Once removed put the LCD panel in a safe place. Face down on a soft cloth.

On the optical panel you will see two metal strips one at the top and one at the bottom and they are stuck to the pannel with double sided tape. The metal strips contain the lamps a CFL type.
When removing these must not bend or flex these strips.
Once removed you will see the lamps which are held in place with silicone rubber blocks and heatshrink plastic, the burnt connection should be obvious.
After removing the suspect CFL tube by uncliping the mount and gently removing it without flexing tube. Clean the carbonized end with circuit board cleaner. In most cases you can clean the copper electrode and resolder the wire back, but before you join the wire sleeve a length of heatshrink tubing over the wire, solder the wire over the tube, the place the heatshrink about 2 to 3mm over the tube from its base. Now you are ready to reassemble which is the reverse proccedure to dissassembly. Using extreme care of course.

If for some reason the tube can`t be resoldered or you have broken it don`t despair you might be able to order the original part or you can use those 300mm ones which are now avaliable from electronics hobby shops, if 300mm is too short, you can chain 3 of more of the 150mm types, don`t worry if they are a bit to big, just leave out the metal strips on reassembly.

The other important thing you may need to help with dissassembly and reassembly is a service manual for the monitor. You can get theses online or with an under the counter bribe with a service agent or TV repair tech.

If you are unsure about doing this, as it is a complex procedure and requires the skills of a neuro surgon, then pass this procedure to a qualified service tech.

However if you LCD monitor has black line across it, then them is the brakes, as this is caused by the ribbon connectors comming loose from the LCD panel and there is nothing that anyone can do about this and the monitor is only good for target practice. That will teach you to buy cheap and nasty.:p

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