Laptop display inverter or LCD

Hewlett-packard / Nx5000
February 7, 2009 at 09:20:46
Specs: Windows XP, intel
Ive got a laptop display that is displaying wierd neon colors and has the text moving all over the place. barely readable.
I hook up a CRT monitor to it and its fine on the CRT.
so I dont think its the vid card or MB.
does this sound like an inverter issue or possibly a new LCD is needed?

See More: Laptop display inverter or LCD

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February 7, 2009 at 13:57:27
Generally speaking, if the external monitor is ok then the problem is most likely to be the LCD screen. The inverter would cause no visible display. If the tube were weak it would cause an orange cast to the display.

Computers... designed to entertain,help with work but most of all to frustrate you!

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February 7, 2009 at 14:11:47
During POST, its a yellow semitransparent neon.
while in windows, blue colored desktop normally, its a semitransparent neon pink.

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February 7, 2009 at 14:27:27
The liquid crystals in the LCD display do not burn out - the backlight = the CCFL - Cold Cathode Florescent Lamp - that provides the white light the liquid cyrstals modify has a finite life like any other florescent bulb.
It sounds like your backlight - CCFL - is dying, and NOT that there is something wrong with the voltage inverter than supplies the high voltage to the CCFL. If the voltage inverter were dead you would see nothing at all. Some voltage inverters go into a lesser mode if they "detect" the CCFL is failing - you may have a brighter display when you first boot, then in a short time it becomes much dimmer.
If you have noticed a reddish or other colored tint to the display before this happened, the CCFL is definately dying.

If you don't want to tackle replacing the CCFL yourself, you can get the complete new display assembly, which can be quite expensive - e.g. $100 to over $200 - (you or someone would have to remove the old unit, install the new one, in the lid), or if your display is common enough, you may be able to find one for less that is refurbished (the CCFL has already been replaced), but it is NOT a good idea to buy a used one, or the complete lid assembly of a used one, if the CCFL has NOT been replaced.
You can probably find the part number of the display assembly here, and use that to search with:

If you're handy and have the tools and are very careful you can replace the CCFL yourself - they're relatively cheap (e.g. less than $20) - but it's a finicky job most technicians won't tackle, and you may need a Maintenance manual to guide you - HP usually has one for your model or model series.

e.g. search for: (your model) CCFL

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February 7, 2009 at 15:15:20
in windows, it does have the red hue to it.
I already tore the inverter out and looked it over for any obvious bad signals, nada.

Since I got the red hue, it sounds like a FL issue.

however, the screen is all over the place. its not a "clean" red hue.
Jittery, scratchy, white specs, and in the upper left hand side of the screen, their appears to be a ring like pattern. Kinda like the rings you see in a puddle of water if you drop a stone in it.

I was thinking, perhaps something gave the LCD a hit right their, damaged the FL and something else to turn the screen all jittery and noisy.


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February 7, 2009 at 23:34:59
"Jittery, scratchy, white specs,"

That doesn't sound good. The LCs and/or their circuits may be damaged. In that case you'd be better off with the display assembly. But if you're into it, replacing just the CCFL is a cheap fix.
Up to about 8 dead pixels are allowed on an LCD screen - they can be any color - if there area lot more than that, that's not normal.

" and in the upper left hand side of the screen, their appears to be a ring like pattern"

I believe that's called a moire pattern.
You may be using the wrong screen resolution, and/or a vertical refesh rate that isn't suitable.
On the other hand, that may go away when the CCFL is replaced - when your display is dim the voltage inverter is not putting out it's full output.

All LCD displays have an "optimal" or "native" resolution at which they look the best - at other resolutions they don't look as good, and the most noticable thing is the text isn't as clear. Try different resoutions until you determine which one yields the best looking text - that's the "optimal" or "native" resolution.

Turn on Clear Type in Windows XP or Vista - makes type/fonts on LCD screens look clearer.

If it's already on, turn it off if you need to determine at what resolution the type looks best.

Many laptops are limited to a 60hz vertical refresh rate, but if you are using Plug And Play Monitor drivers, you may be able to set that higher when you shouldn't - see Display - Settings - Advanced - Adapter to see what it's set to. If that's too high, setting it lower may get rid of the moire pattern, or just try other rates.

If you dig around looking at the specs for your model, you may be able to determine what vertical refresh rate(s) is(are) safe to use with the display, and maybe the specified "optimal" or "native" resolution.

Laptops often use Plug And Play Monitor drivers, but some of the settings you can choose in that mode do not look right or can actually damage an LCD display - they were designed primarily for crt monitors, at the time when XP first came out, and I don't think they've changed since.
You could look on the HP site to see if they have specific drivers for your display, in the downloads for your model or elsewhere, but you may not find any.
Standalone LCD monitors usually have specific drivers you can load to avoid possibly damaging the display - by default Windows then only shows you the settings both the monitor and the video drivers can display safely and properly.

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