LCD Monitor Troubleshooting 101

image It’s a safe assumption that the vast majority of computer users today use LCD monitors. It is in fact a very reliable technology and it’s not often that you hear of one breaking. But being that it’s an electronic device, yes it will eventually fail.

How long does it take before an LCD fails completely?

Usually about 5 to 7 years.

What is the first thing to "go" on an LCD monitor?

With a free-standing LCD (i.e. one attached to regular desktop computer), the backlight is usually the first thing to break. With a laptop a whole host of other things can go awry. More on that in a moment. When a backlight fails, the picture will get extremely dim. It will still work but be almost unreadable.

Is it worth it to repair an LCD monitor?

Never. The cost of repairing an LCD monitor will usually cost more than replacing it outright.

Common issues with LCD monitors

Solid horizontal and/or vertical lines

One day you will turn on the monitor and these brightly colored lines will appear with no way to get rid of them. This is a hardware fault and there is no fix for this. Replace the monitor.

Monitor takes a while to "warm up" after starting it

You turn the monitor on and it takes a minute or two to reach full brightness. This is a backlight issue. You can still use the monitor normally until the backlight breaks (which it will eventually).

Monitor flickers on and off randomly

This is laptop-specific. The LCD ribbon connector cable is damaged from normal use of opening and closing the lid over time. This can be repaired. The monitor does not need replacement, but the ribbon connector cable does.

If you’re brave enough you can order this part from the OEM manufacturer and replace it yourself. It it normally located under the left-side hinge. It is not easy, but certainly cheaper than replacing the entire display.

Suggested course of action is to locate an authorized computer repair center and have them replace the ribbon connector. It will cost anywhere from $60 to $150, labor included. This may sound expensive but it’s still cheaper than replacing the monitor itself which will cost a whole lot more.

Corners or one side of monitor appears dimmer than the other

Again this is a backlight issue. There is no fix. Deal with it or replace the monitor.

Everything "goes green" or "goes pink" or "goes red"

For laptops, again this is the ribbon connector cable. Replace it. For desktops, replace the monitor cable which may or may not fix the problem.

"Wild patterns" appear for no reason

It will look something like this:


No fix for this. Monitor is busted. Replace it.


  1. What about automatic adjust. I don’t press the automatic adjust button but sometime my monitor start adjusting itself. Adjusting more then 20 times, and then he will stop. Passed more then 1 year, and i still can find some solution about it. It’s Samsung SyncMaster 720N.

  2. Steve Stone says:

    Nice keyboard in the photo. Looks like the original for the IBM 5150 PC. You could get an 8 bit full length VGA card for those beasts towards end of life.. which means you could plug an LCD display into an 8088 based rig. That description for the failing ribbon cable between the LCD and the laptop innards is similar to a problem I had with a Thinkpad T41.. but it required a motherboard replacement. Too much flex of the MB planar results in marginal connection between the ATI chipset sub assembly and the motherboard planar.

  3. My LCD had been faithful for 4 1/2 years but then when first turning on my background would come up but in a split second it would fade to white…sometimes I could get it to stay on, so I decided to leave it on constantly. After a week the picture went black. When I turn it on I have a quick flash of light then it’s no picture. It has built in speakers and they seem to work. Are you able to tell me what’s wrong?!

    • sound like bad capacitors, if youre handy with a soldering iron, replace the caps in the monitor. takes about an hour but it should fix the issue.

  4. I recently had a problem on my laptop where the bottom half of the screen was brighter than the top half. I opened the bezel and found no obvious problems. Out of something just to try before I saw about getting it repaired, I loosened one of the four screwes that secure the panel into the metal bezel frame and the problem went away. Looks like the frame was putting pressure on the LCD and causing the problem.

  5. With regard to getting a ribbon cable changed as suggested,I wouldn’t bother because you can buy a new monitor fairly cheap no matter what the repair. Also not many electronic shops bother repairing them.

  6. I’m hoping you can help me here. My lcd died tonight. It’s only about 14 months old and the screen just dimmed like it was going into sleep mode. Power stayed on, and backlights look to be on. Just no image. No OSD even. The monitor does recognize whether or not it’s connected to a computer. I tried both the VGA and DVI inputs with the same results.


    • Try connecting monitor to another computer first to rule out video card issue. If the monitor doesn’t show a picture on another computer, either the connector cable is shot or there is something internal within the monitor where the video signal is not being transferred to the screen.

      • I’ve tried both of those and still no image. Are there any parts that would be in the video signal path that typically fail? I’ve mostly only heard of power supplies, inverters, and backlights going out. This seems like it’s more serious.

  7. My View Sonic VX910 flat panel display started coming on for about a second then the screen goes off. The power button stays on as usual. I’ve tried it on another computer and get the same results. I replaced two capcitors on the power supply board but still the same thing happpens. I haven’t been able to find a schematic or parts list so I’m still looking for answers.

  8. Y’all might consider that there are sources for the Cold Cathode Flourescent Lights (very thin and delicate) and the inverters that drive them to fit the majority of laptop LCD screens. Look around online, I opinion neither are expensive. Also take a look at Morris Rosenthal’s Win/lose/draw, you may discover why things went bad. Good Luck.

  9. actually I believe the last problem might be fixed by replacing the input board (which is an easy task to do, but not an easy thing to find)

    John Micknal: If the caps are bad for long enough, the lack of electrolitic forumula will cause more voltage to pass to the components in the circut with the caps, resulting in those being damaged.

    Oh yeah, the same thing happened to my mothers Viewsonic. I opened it up and what brand did I see on the inside? Haans-Star. Otherwise known as Haans*G, who tends to use crap parts (esp caps)

  10. I just bought HP 1740 LCD flat screen monitor off from ebay. I used it less than 2 hours now it doesn’t power up. I have changed power cords. Any ideas?

    • Darlene, look to see if the LED next to the power button is staying green or does it go to amber. If it stays green then your backlight PCB is the problem. I have a few of the same model and when I find a solution I will post the fix.

  11. I disagree with the statement taht says it is not worth repairing these monitors. I have repaired many. The average repair has never exceeded $50.00 to the customer. The monitor is considered refurbished, and is saved from the landfill.

    • Dan, What is the most common problem? Are you doing component level repair or board swap? Does recapping the power board seem to fix most backlight failures or are you replacing the step up xfmrs?

      • Defective capacitors are common, soldering issues are next, due to heat. I will usually test and replace all electrolytics, then go over the boards and resolder everything.

        • Thanks for reassuring my initial thoughts. I have 25 or better HP 1740’s that I can not find schematics for, but fortunately I have a working one for comparison. These all power on and initially and show with the back light then either flicker or just go dark yet the monitor still still indicates a valid signal. I did not notice swollen caps but it wouldnt be the first bad cap that doesnt show visible expiration. as soon as I get spares I will post the results.

          • If you were located in central Ontario, I would be glad to try and revive as many of those HP’s as possible…

        • Hmm… One of the HP 1740’s in my high school’s CAD/D room seems to be having the same problem. Screen shows an image for a second with a red tint, then starts flickering, and finally seems to lose signal, but on closer inspection, it’s just dim, as if the backlight isn’t working. If it’s a capacitor issue, I could probably repair it.

          If / When you find the schematics for them, would you mind posting a URL? I’d hate to see the school’s IT guy toss the thing in a dumpster. They’re pretty nice monitors, at least for my low standards in video technology 🙂

  12. I am working on a Westinghouse 19 inch flat screen lcd there were two capacitors that were questionable as the tops were sticking up not like the rest of them which were flat, I replaced all of them with the correct values, still not getting no voltage to the bulbs.
    Any other ideas on what to check????
    Before changing the capacitors the light on the side of monitor would stay green as long as video was going to it, but no light to the display, this monitor is not two years old.
    Would appreciate any help or suggestions—-

  13. Hi,

    I have a compaq presario v5000. My lcd screen recently started giving me problems. 1/3rd of my LCD screen went black. My laptop readjusted the screen side to the 2/3rd portion and I can see the entire desktop. However, the top 3 inches of the screen are displayed on the bottom 3 inches as well.

    I cant figure out what the problem is. Is it dead pixels ? But does the computer readjusts itself to a new screen size ?

    Please advice. I can also mail you a picture of my lcd display if you provide me your email.


  14. Hi all,

    I’m an old electronics tech from the navy and know that everything we use is repairable. The only thing lacking for me is the whereabouts of block diagrams and schematics. Are there any available? My Neovo is experiencing a vertical line problem. I can rap the side and get it to stop displaying these random lines. Sometimes the screen is full of them other times it is only in small rows. My first task will be to open the case and see if there are any obvious problems. The next thing to do will be to resolder the components that are subject to heat. I might use a plastic wand or a toothpick and tap around on different components until I find the one that is causing the problem.

  15. Had A Red Monitor Thanks You It’s Now Gone

    Many Thanks

  16. Kwai Chang says:

    I have a new flat screen monitor. When using the VGA connection to the PC, the desktop has ghosty wavy lines. I replaced the cable with a DVI cable trying to eliminate the lines and increase the quality of the picture. The PC has DVI-I output, the monitor has DVI-D input. The cable is DVI-D to DVI-D. When selecting the DVI input on the monitor menu, the screen goes black.

    I can find no information that allows selecting either VGA or DVI output from the graphics card, so must assume they are both hot.

    What can be wrong?



  17. Kwai Chang says:

    FWIW, I got it to work. Had to set the computer up for shutdown, with the final mouse click waiting. Set the input to DVI in the monitor’s menu, then clicked the mouse. PC shut down, then I detached the VGA from the video card. That seems to have been the secret, along with doing a cold boot. The monitor found the input, and it works now.

    Thanks anyway!


  18. i have IBM 15 LCD Thinkvision amber light flickring when power on. actually what is the trouble can it be repaired



  19. I have an LG L1915S LCD monitor that’s a few years old, and it just recently quit working. I unplugged it and plugged it back in, and for a second the little light by the power button flickered on, and then off. The monitor is only a few years old, but it does get a lot of use. I’m fairly sure it’s not a video card issue, because it seems as if the monitor itself won’t turn on.

    I also tried another power cord, and that didn’t seem to do anything. It can’t be the power bar, because the tower for my PC as well as my speakers are running off of the same bar, and changing plugs on the bar didn’t do anything, either.

    Any ideas?

  20. Randy Carpio says:

    We have similar problem. Mine is an LG L22WTQ, 2 years old LCD monitor. Just as what you did, I had already isolated the problem, not an AVR problem, not a power outlet problem, and not a power cord problem. I also tried replacing the male power cable port, the one located at the back of the monitor, but still, the problem is unsolved. Sometimes, my monitor works, and sometimes, it does not. About 2 to 3 times of unplugging and replugging the power cord connected at the back of my monitor resolves the said problem. But then, I want to resolve it totally. It might be an electronic component problem. A capacitor?…… or something related to it…… Anyone who knows how to troubleshoot this problem would be very much appreciated……

  21. Please can you help me to solve my problem,as follows:
    I had replaced the old CRT in my computer with new LCD Ttype LG FLATRON W1942S but after one month I face aproblem when I am using walky talky few meters far away
    then the LCD power becoms OFF & ON after that this happened again but the LCD did not work with no power light only if the walky talky pressed transmit the power light goes ON without bright in the screen.
    Thank you

  22. i also have an LG L22WTQ, 2 YEARS OLD then one night it went weird on me! The display went grainy, and the contrast/gradient is very harsh on videos and pictures. I have reset to default properties in the display screen and I definitely know it is not my graphics card, or connectors as I am having no issue running an HP W2216 using the same settings and objects. I have sent the product to lg to be fixed, however they did not seem to resolve the colour issue. Does anyone know why i am having this problem (with the monitor/troubleshoot) so I can understand what i am talking about when I call LG again.

    Any help would be much appreciated

  23. What about a pure white screen .

    i was on the internet , then out of the blue , my screen went completely white. In a matter of about 2 seconds , i had no images, just a plain white screen.
    I removed the monitor , and plugged it in, just the monitor alone , and nothing but a solid white screen.
    I hooked up my spare monitor , and it was fine , everything was working well.

    What could have caysed this so suddenly, it was instant.
    Can it be fixed.
    comments appreciated


  24. What about a pure white screen .

    i was on the internet , then out of the blue , my screen went completely white. In a matter of about 2 seconds , i had no images, just a plain white screen.
    I removed the monitor , and plugged it in, just the monitor alone , and nothing but a solid white screen.
    I hooked up my spare monitor , and it was fine , everything was working well.

    What could have caused this so suddenly, it was instant.
    Can it be fixed.
    comments appreciated


  25. I have an LCD monitor Philips 170S6, which recently started showing a message: “Attention! Security Flag Off”. Could someone share how to fix the problem. I hasn’t done something like that before. Please help.

  26. Hi,
    I have a dell inspiron 1420 and while i was using in my monitor suddenly started displaying white as pink black as flourecent green and the hole screen looks fuzzy (as if part of the picture is copied over a milimeter to the left)
    when i connect an external monitor it works fine.
    any help or thoughts on what the problem might be would be appreciated.

  27. I had a dell inspiron 1420 that had horizontal wavy colored lines that looked somewhat like static lines, and had distorted images. I replaced the LCD display with a Dell refurbished LCD display. WORKS GREAT

  28. I have a problem with monitor. When I start computer windows start normaly , but monitor just stay black. After restart computer everything is normal, windows and monitor start. What is the problem? Thanks!

  29. You know, at first I thought this article was written by a fairly informed person, right up until I read this: “The cost of repairing an LCD monitor will usually cost more than replacing it outright.”

    I’ve been repairing LCD monitors and TVs since they hit the market. Who ever told you they are not worth repairing? We repair boards (main, power, inverter) and replace backlights. Repair costs usually run less than half the price of a new monitor.

    For example, repairing a 22″ LCD with a bad backlight would cost about $60 labour and $15 to $25 for the light. Making the repair $75 to $85 Canadian (U.S. and Canadian dollars are pretty much at par right now).

    Often the problem is a few capacitors, which would reduce the cost to under $70. A 15″ or 17″ monitor would run $50 labour, and in the case of the 15″ may not be worth repairing unless you are using it in a specific location because of its small size. (We get units from stores and restaurants all the time and they are happy to pay to get a 15″ monitor repaired).

    Usually after a repair the monitor works like new, and often better than new because we don’t use the substandard parts many manufacturers use.

    I often see LCD monitors and TVs in trash bins around our city, and I am forced to wonder why they didn’t try to have it repaired. If the trashed units are in good condition, I will repair them and sell them at 1/2 the cost of new.

    Please, if you don’t know about a subject don’t write about it. Some of these people may have thrown out valuable monitors that could be repaired at a worth while cost because they read on your website that’s it’s not worth repairing them.

    I’m just amazed at how many people who use an item for a while, or even multiple items, think this somehow makes them an expert at electronics. If you don’t do the repairs, then don’t write about it. You just make yourself look foolish while passing FUD to people looking for accurate information.

    • You didn’t seem to send any links to back up what you said, so I will.

      Your quote on the 22-inch repair is wrong. 22-inch and up is over $100 for repair. You must work real cheap.

      A brand new 22-inch is $159, with free shipping I might add.

      I’ll spend the extra $54 for new with a 3-year parts+labor warranty. And although this is just a wild guess, I’m fairly certain you don’t offer a warranty that comes anywhere close to that for the monitors you repair, assuming you even offer a warranty at all.

      • We offer a 90 day warranty as is standard in our industry. Most people here purchase their monitors from stores. I myself just purchased a 23″ Samsung 16 x 9 fpr $197.

        Prices are coming down fast, however that doesn’t stop people from getting their monitors repaired, as we do it every day. As I stated, our price for a 22″ LCD monitor repair is $60 plus parts. $60 is an hours labour. Anyone of reasonable skill can repair any 22″ LCD monitor in under an hour. If you’re quoting $100 (or more) then that is either for a board replacement or it’s from “Rip Offs Are Us”.

        We actually repair boards, having been trained in surface-mount. You know, a technician? Not some Robertson Career College grad who’s only been taught to swap boards.

        The fact is 90% of repairs stay repaired. Those other 10% get their money back, or they get a free repair on us so it stays repaired.

        This all goes back to my original point. LCD monitors are perfectly repairable, often under half the cost of a new monitor.

    • Hi John!
      I’m with you! We throw out way too stuff in our society. The best way to recycle products in our world is to keep using them. I sure would appreciate your assistance and guidance with a ViewSonic VG175 a friend has given up on. We need one and things are tight (as I’m sure you’ve seen up there, too). I’m having no luck finding repair and diagnosis manuals that don’t cost as much as a new monitor. Any help and direction would be appreciated! Thanks, Dave

  30. Please assist….my Sony Bravia 32″ LCD screen exhibits a dark cloudy mark which blends in to some images but irritates when a light background is present. The device is two years old. What is wrong and can it be repaired?
    Many thanks

  31. Another reason a laptop display may flicker is the ‘Inverter’ is on its way out. In the same way as a flourescent tube flicker may be caused by the ‘starter’ failing, an LCD backlight may flicker due to the inverter board (which generates the high voltage needed to ‘kick’ the backlight into operation) starting to fail.

  32. hi…
    I Have a dell inspiron 1420, my LCD is flicker for about 2 second interval.

    I know This is not a driver problem, because when I open the BIOS Menu this problem still occur.

    Anyone help me please,,
    i bought this laptop about 2 Years,,

  33. EzyPeezy says:

    You are goofy. It's not all that hard. Some of it is just plain easy. I won't tell you though.

  34. Curtsbigguns says:

    I have a problem with my Monitor. For some reason my monitor isn't displaying different shades of color properly. Some colors are smooth but others seem to have tiny vertical lines which seem to appear more in darker colors. Is this fixable or do I need a new monitor?

  35. Carolyn alston says:

    My gateway lcd computer monitor blurs when bumped, if I bump it hard enough the picture clears up for a liittle while but then gets blurry agian? What is causing this? Thanks.

  36. I still can't believe how many “black-screen-of-death” lcd monitor owners have not viewed some of the “lcd monitor disassembly” and “lcd monitor repair” videos on YOUTUBE!!! Some units can be repaired on a DIY basis for less than $6 US in parts. I'm 12fixlouie over on fixya. com

  37. Very helpful. Thank you. I’ve been frustrated trying to open this .efw file, yet all these sites I’ve pulled up to help me only want to install new software for a “free” scan, then charge me for what may or may not be a remedy. I know where to come for advice from now on. Again, thank you.

  38. i also have an Ge L22WTQ, 2 YEARS Previous then one night time the idea travelled unusual on us! The display proceeded to go grainy, and the contrast/gradient is very harsh on movies and pictures. I have recast to default qualities in the display screen and I surely understand that is not our graphics card, or perhaps connectors as I am having simply no issue operating an Horsepower W2216 using the same configurations and physical objects. I have routed the product to whirlpool to be set, on the other hand they did not seem to solve the colour issue. Really does anyone realize precisely why i am having this difficulty (with the monitor/troubleshoot) so I can understand what i am talking about while i call Ge again.

    Any support can be a lot appreciated

  39. Casandsurfsnow says:

    What is wrong with an LCD monitor when I change from 60Hz to 120Hz and every other vertical line is blank?

  40. From R Sridharan
    I am using a LG LCD monitor connected to the desktop. On startup it changes color.After switching off and on the monitor it restores its original color. It happens every time when I boot the desktop system, Why does this happen? Please clarify

    • Hello and welcome to PCMech! To get help with your question, I encourage you to start a new thread in our community discussion forum where our resident tech experts will be happy to help you trouble troubleshoot further.

  41. I have a LG m2362d monitor that developed a red vertical line on the right side of the screen, I cleaned the cable contacts & I was wondering if changing the logic board would fix it?

  42. Hey, hello. I have a LG Flatron W1942S monitor & yesterday it didn’t want to turn on at all. The diode on it, didn’t even change color at all, just was grey all the time. I wiggled around the power cable & somehow it turned on. Today I wanted to turn on my PC, but the monitor didn’t turn on at all, the diode sometimes turn on for half a second & then goes grey. Trying to troubleshoot what is happening for the past half hour.

    P.S. I have LG Flatron W1942S monitor

  43. Harold Niemeier says:

    Hello , I.recently received a CORNEA MP704 monitor that when I went to connect the power supply I realized that it had no center pin in the connection. I dissembled all the way where I was able to de-soldered the adapter plug port from the mother board and replace only the center pin in the connection and then resoldered it back to the mother board . Upon disassembly I had to unplug the ribbon that was for the front user circuit board ,the LCD connection at the screen and mother board , I then unplugged 2 top and the 2 bottom back light connections from the power board removed mother board from casing unpluged 2 additional ribbons from main power board to mother board . After reassembly and connecting it to my tower when I powered every thing up my monitor would flicker on then off for only a fraction of a second for about 3-4 times only during boot up . The power light would stay constantly lit till I powered off the tower then it would blink as normal . Turning on the tower again would have the same results . I then connected my laptop to the monitor and that also give the same results as the tower . I decided to dissemble the monitor once again to double check the connections and noticed the ribbon connecting to the front user panel was not quite all the way plugged in and 1 of the 2 bottom back light plugs had 1 of the 2 pin connectors making contact. I reassembled everything back together ,powered it back up and wa-law it works perfect . My experience with a flickering monitor tells me that the problem is associated with the back lights in the monitor and for anybody that has had work done on there monitor well you better double check your connections. Hope this might help

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