Repair a Flatscreen Monitor for $15





Introduction: Repair a Flatscreen Monitor for $15


I found an LCD flatscreen monitor on the sidewalk. Took it back to the lab, turned out the screen was pretty dark, especially on the bottom half, so I figured the backlight was broken. I opened it up and found this to be true. turns out one of the two outputs of the power inverter that fed the two backlights was broken. I had a set of CCFT lamps + inverter ($15--> lying around from a previous project (lighting a sound proof temperature controlled experimental box) so I decided to pop one in. Here's how I did it (it worked great).

Step 1: Open It Up Carefully

FIRST OF ALL, BE VERY CAREFUL, THE CCFT LAMPS CONTAIN MERCURY GAS WHICH IS VERY POISONOUS. I take no responsibility if you are in any way injured by mercury gas or any other procedure described in this instructable. To be safe you should do this outdoors or in a very well ventilated area in case the lamps break.

having said that, open the monitor carefully. There will probably be at least two or three weird overlapping wire connections (see picture) which you'll have to carefully unplug to get everything apart. Inside you'll find the LCD screen, a thick glass/plastic light diffusion panel, some thin plastic light diffusion sheets, and two CCFT (cold cathode flourescent lamps)backlights (at the top and bottom of the LCD screen).

Figure out which lamp doesn't work. This may be because the lamp itself is dead, or because an inverter output is dead (the lamps use AC which is converted via an inverter from the DC sent to the monitor). These lamps take high voltages, if you plug in the monitor to figure out if the lamp is broken be careful.

Step 2: Put in Your Lamp

buy a CCFT kit from allelectronics or some other place ( If the lamp will fit in the monitors case without obstructing any of the other pieces (the light diffusion glass/plastic, or anything else). Then you're set, just pop it in and secure it somehow.

In my monitor, there was barely enough space between the light diffusion plastic and the case wall to put in my lamp so I had to cut up the case a little bit.

I also put a strip of cardboard behind the lamp to elevate it to the level of the light diffuser, otherwise it was too low.

Step 3: Test It Out

you should be able to test out the monitor with its new backlight(s) without putting the case back on. If you can't get it plugged back in to a computer to test the LCD + lamps, then at least test the lamps behind the LCD (without the LCD turned on). Just to see if they illuminate well in the position to placed them.

In the picture below I'm testing out only the bottom lamp I replaced. Works well.

Step 4: Put It All Back Together

put everything back together. This can be a pain cause of the overlapping plug connections. Make sure to dremel a little notch on the outer case so you can snake your lamps inverter cord out (the inverter will have to have to be powered by a seperate power outlet).

Make sure you don't forget to put all the pieces back in (I forgot some and the ommision makes my LCD slide around a bit)

Step 5: Test the Whole Thing Out If You Haven't Already

test it out plugged into your monitor. See the with and without replaced lamp picture below.



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    I'm an electronics engineer. I've spent 5 hours repairing a $3 transistor radio many times. It's not the money (well, not always). It's a challenge, a game. And when I go through the radio (or??), I make improvements. First, I "bullet proof" (replace/modify parts/circuits most likely to fail). I'll replace an IF transformer with a ceramic filter, improving selectivity and fidelity. I use larger interstage caps and rebias sections that are distorting. I might add a 3 watt mono class D power amp, power it with D cells or a 6 volt 7 amp hour gel cell, add a charging circuit that won't fry the battery, and mount it all inside a nice speaker cab. I *hate* those little tiny tuning wheels and usually replace them with vernier knobs. These are very accurate, and eliminate the need for digital displays. I snap up vernier dials for pennies on the dollar at ham swap meets, estate sales, and such. Some of these are 30:1, and built like They're too expensive (new) for consumer gear. They're fairly routine on lab gear and military electronics. I *LOVE* JAN (joint Army-Navy) and MIL SPEC surplus.

    I have an old Gateway FPD1800 flatscreen momitor (circa 2000) that doesn't seem to work when I give it power and turn it on. I can see the green power light turn on then it quickly turns into a somewhat yellow color. But nothing is happening on the screen. the "no signal"/ "loss of signal" window doesn't even show, the screen is just black. Can anyone possibly tell me what is wrong with my monitor? Please excuse the unprofessional style of the following pics.

    7 replies

    Did you ever figure out a way to repair the gateway monitor that was going to sleep. I have an Acer CRT monitor that is doing the same thing , green led , then it goes back to sleep (orange)  like there is nothing connected to it. The connector is fine, the VGA card works flawlessly , and the Hz signal is within monitor specs so ? what could it be?.


    It sounds like the power supply is going into power saving mode (like standby mode) and won't come out. I have one with the exact same problem that some time or another I will fix.

    is there anyway to stop  a moniter going to standby when theres no input signal ? i have a bust moniter and am wanting to use the backlight ( i cant seperate the inverter from the mainboard cause i cant figure out the 4 wires to make it work 12v . any suggestions would be great because its been on the workbench for a week and its doing my box in . thanks

    If it is the inverter and you definitely can't fix it or find it, you can buy a suitable inverter board on ebay fairly cheaply if need be. I will have a go at repairing my inverter but still had no chance to do it. It's quite often a separate small circuit board. Usually obvious as it is connected to the backlight not the LCD panel.

    hi legless when you fix your monitor could you please do it as an instructable as my monitor is behaving exactly like you described. Hopefully you'll feel like having a go in the very near future. Thanks! regards Lyn

    Have you tried a new adapter? There are lots at <a href="">12V Power Supply</a>.

    ohh nooo!! Tell me thats not a viewsonic!!! I have one exactly like that, with a burned out inverter!!!
    Hmm I may try this.....

    all LCD monitors, yes. Even on palm pilots and cellphones.

    Not necessarily. At least not Cold-Cathode Lamps. Recently, they have been moving to LED backlights. small appliances (cell phones, PDAs) especially...

    And Apple's new LED cinema display.

    a lo of laptops especialy netbooks are led nowdays

    i'm not screwing around with mercury gas to save a buck.

    just curious, why not tap the power source from the burned out backlight, for your 12V source to run the inverter?

    1 reply

    it's funner my way :)