Easy Laptop LCD Screen Diagnostics: Bad Backlight(?)

To Backlight or Not to Backlight? Is it Actually Broken, That is the Question:

So, you think you’ve got a bad backlight or a tech-savvy friend of yours turned on your laptop and said you have a bad backlight. .  . spoiler alert: there’s a big  (and important) difference between your laptop’s LCD backlight not coming on and the backlight actually being broken and unless you’ve fixed a LOT of  laptop LCD problems in your lifetime, this tends not to be something one knows.  A broken backlight means that the backlight is what needs to be replaced; a backlight simply not working, on the other hand, may have any of several sources, and a broken backlight is rarely the most probable cause.

Just one note before we get started: if your LCD screen comes (or used to) on somewhat (not entirely) dim or with a red discoloration or it comes on and flickers from the get-go, that’s usually a dying or dead backlight.  Proceed to our article on replacing your backlight the easy way!

First off, let’s cover some things that are not caused by a bad backlight

  • Garbled screen with weird ‘artifacts’ at random times
  • Laptop screen powering off or going wonky after a long period of use.
  • Lines on the screen
  • Screen appearing ‘shaky’ (weaving left to right or up and down at times)
  • Generally: If your screen stays bright, it’s not the backlight.

So, why wouldn’t your laptop’s backlight not come on, even though the machine seems to be powering up?  There are four reasons major reasons (and I’ve yet to come up with a fifth):

  1. Your laptop is not actually booting up (though part of it may be powering on, drives are spinning up, indicator lights flash, etc., it’s not actually doing any computing)
  2. Your laptop screen has a bad inverter.
  3. Your laptop’s motherboard has a damaged or bad video card.
  4. Your LCD’s backlight is actually bad.

To be a little more sure, the first thing you’ll want to do is to turn on your laptop and have a close look at the screen under decent lighting conditions.  Power on the machine.  If your laptop’s LCD screen is not ‘lighting up’ but is showing a faint image on the screen (if you look very closely under reasonable lighting conditions, you see a very faint image on your screen that looks like what ought to be there, but isn’t lit up), then we know at least that your laptop is booting.

If your laptop screen is not lighting up, you’ll want to have tried both of the following before attempting a backlight replacement:

  • replace the inverter with one of the exact same part number1 (no, not just one advertised as matching your model of laptop, really, you’ll thank me later).
  • inspect the LCD cable and found it in good condition and made sure it’s snugly in place.

If neither of those have fixed your problem, then attempting to replace your backlight is going to be the most cost effective next step in trying to fix your non-working screen.   Replacing your motherboard is the last thing to try.  We recommend you hold off on that until you’ve exhausted all other options.


1 I should note that Green Penguin Inc. does upon occasion advertise multiple compatibilities or even a part number as being compatible with most or all variations of a particular laptop.  In these cases, we have done extensive research into the matter, often having already tested and disassembled 30-40 different versions of the particular model of laptop in question.  I can’t guarantee it with anyone else and I want this information to be useful to you whether you purchase from us or not.   I want the result of your repair experience to be that if the part you’re replacing is faulty, the replacement fixes your problem, not makes it worse.

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2 Responses to “Easy Laptop LCD Screen Diagnostics: Bad Backlight(?)”

  1. January 17, 2012 at 5:10 pm #

    Hello Gpenguin,
    Thanks for your thoughts Among thousands of blog posts put out everyday, how do people decide what they will read? It may not be the only factor affecting people’s decision, but there’s a very good chance people judge your post – and perhaps your blog by your titles. A good title grabs people’s attention, makes them look twice and take a few minutes to click through to read. A bad one… well, doesn’t even register on the radar.
    All the Best

  2. Hawnrippa
    February 2, 2012 at 11:38 am #


    Another thing you can try is to hook-up an external monitor to see if computer boots up and screen appears normally. However, that still does not pinpoint what the issue could be. Could still be the LCD screen, inverter or possibly the motherboard even though the the external monitor works.

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