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View Full Version : Laptop screen backlight keeps turning off??!


Feneris
20th Jun 2004, 20:53
I've run into a prob no amount of head-scratching seems to resolve. It's a Dell Inspiron P3, and inevitably just over a year old. The screen backlight keeps turning it's self off in Windows XP, and has also done the same while looking at the BIOS setup screen. When it works correctly in XP, at times the backlight flickers and the screen may also be a bit pinkish. After the backlight has turned off, anywhere between a minute and and hour, it will only turn back on by using the Fn (Function key) and the Suspend key on the keyboard. This pops up the Shutdown/Suspend/Restart options and turns the backlight on again. The Fn+key to use external monitor instead, doesn't turn the light back on.

If it had never turned off while looking at the BIOS setup I would blame XP, but it doesn't seem that simple. The girlfriend has loads installed and doesn't want everything wiping for a re-install. All powersaving options in XP and the BIOS have been disabled. After calling DELL they think it's the graphics card (£250 please!). Anyone have any other ideas, or ideas on how to better diagnose it.

Thanks for any ideas, F

NW3
20th Jun 2004, 20:58
Feneris - unfortunately that sounds like quite a sound diagnosis from dell. It doesn't sound software related, so it's then a question about which bit of hardware. If it was just the screen that was randomly knackering, then it would be odd if it *happened* to un-knacker itself when you did the Fn Suspend keypress... somewhere in between lies the graphics card, and so that would make sense to me.

You could try plugging an external monitor in and seeing if it exhibited any strange behaviour.

NW3

Naples Air Center, Inc.
22nd Jun 2004, 14:21
Feneris,

You could try in Display Properties >> Screen Saver Tab >> Power Button. Set Turn Off Monitor to Never.

If that does not solve the problem, there is a small possibility that the ribbon that connects the screen to the motherboard, might have slightly pulled out. If not, then you are looking at either a new screen or a new vid card.

Take Care,

Richard

Tinstaafl
24th Jun 2004, 13:42
There's another possibility.

If you shine a bright light onto the screen can you see a (very dim) image of whatever software is running? It will be dim because you're relying on reflected light from the LCD instead of transmitted light. If so then the failure is either the backlight or the inverter board that powers the backlight. I include the wiring for these when I say this.

If it's the inverter then it can be a cheap fix - replace the board & away you go. My old Twinhead PII's inverter board costs ~15 quid.

If it's the fluoro. backlight then it can get rather more expensive to obtain a suitable replacement light. Presuming that it's possible to separate the backlight from the LCD screen without damaging the whole thing.

Engineer
24th Jun 2004, 16:11
If it is the backlight it is relatively simple to replace but as Tinstaafl states it is locating the correct tube and that can prove expensive.

As for the inverter surprised you got it so cheap and what's more was able to source the part for a twinhead

Feneris
29th Jun 2004, 21:53
Thanks for the replies, still playing with it, but will probably end up using a Dell specialist to repair it.

Thanks, F

Naples Air Center, Inc.
30th Jun 2004, 05:17
Feneris,

Any idea what the "Dell Specialist" is going to charge for the repair?

Take Care,

Richard

Big Kahuna Burger
30th Jun 2004, 17:39
This is going to be really annoying as I cant remember where I read it but....

An article recently stated that the 12mths guarentee is actually more than that.

Have a look here.

I dont think its as black and white on the 12 mths that we were once used to...


http://www.dti.gov.uk/ccp/topics1/facts/salegoodsact.htm

Tinstaafl
30th Jun 2004, 18:46
Engineer, I ordered the inverter board direct from Twinhead UK. So far I've bought two through them, a DVD drive & various of those tiny little screws that had gone missing over time.

Sir Richard
1st Jul 2004, 07:04
Could be as simple as a loose connection! My 3 year old Sony Vaio had similar beahviour after repeated dropping (just careless I guess!) Some work with a small screwdriver and an inquisitive nature led me to dismantle the beast where I found the loose connection to the screen. Put it all back together with no bits left over, and it now continues to work perfectolkzxdjm .ksjebv.,mdasnfv ............:D
All done within a couple of hours in a dimly lit hotel room. :ok: