BleepingComputer.com: backlight going out intermittently

Hi. i have a dell 1200 laptop. the backlight goes out sometimes after a couple hours, sometimes every couple of minutes. tried everything os related to fix it(i.e new drivers, display settings, updated bios, etc), with no luck. Any ideas on possible causes and fixes? any help is appreciated. thanks.

Hi JQ11, I am hoping I can help solve your problem.
Just asking this question to have a better understanding of your problem.
You say the back light is going out, right? What I need to figure out is if your battery saving feature is kicking in, or if you have a damaged or pinched wire in the laptop's hinges.
What happens when you shut down and re-power up the laptop? Does the display's back-light now work again and then shut off after a while? Does this happen about the same time in minutes and seconds every time it happens? Time it and see if this happens at the same moment it did the last time it happened.
This will help me detremine if your battery saving feature is what is doing this.

Waiting for your reply.

Hi. thanks for the help. it does not seem to happen at any predictable intervals. it has happened every 10 minutes or so at times and then won't happen again for 3 or 4 hours. It has happened while the battery was removed and working solely on AC and has happened while on battery power. the screen will usually come back when i close the lid, wait 20 seconds or so then open the lid. but a couple times that has not worked and i have had to restart the computer. no errors are being recorded in event viewer. let me know if there are any logs or files i can copy and post that may help. thanks

Ok event viewer will mostly log an error if it was windows related, since this is not the case here, we now know it is related to your laptop's hardware, which windows does not control.
I now need to determine if your backlight is causing an over heated circuit to shut the display down, if the laptop has a damaged wire in the hinge, or if a laptop control feature is turning off the back light to save battery power, or if there is a feature enabled that saves the back light from premature burnout, that some-how was enabled in the laptop's BIOS settings or a keyboard shortcut combination was activated by mistake (usually a FN (function) key) that enables the function features shown on various keys on the keyboard.
The Function key's lettering color (usually blue lettering) works with the functions on verious keys which the lettering is the same color. (in my example the letters would also be blue)
Both the Fn or Function key and the corresponding keys have to be pushed at the same time.
Hopefully I'm not confusing you here.
One function key has to do with the backlight.

This post has been edited by MrBruce1959: 05 February 2010 - 03:50 PM

I want to add one more question, this is related to Windows Power Management.
When this backlight problem happens, what is happening with the laptop at that time? Does it happen while you are actively using it, or does it happen only when it is sitting idel for a while?

This post has been edited by MrBruce1959: 05 February 2010 - 03:26 PM

not confusing at all. your very clear. it does have function keys. there is one that says "standby" but when pressed nothing happens. i'm farely certain its not battery related as it happened even when i removed the battery and had it running on ac power. is there a way to check the wires? I also dont think its a power saving feature as its happened while i was actively typing. confusing one for me.

OK, but the reason I was talking about the battery saving feature is because the laptop I own, shuts the backlight off after a while even though its powered by the AC power adaptor.

I see. definitely could be that feature malfunctioning. i changed those settings in the os to never to turn off but that didnt help. in the dell battery manager it i cannot find any adjustable settings for battery management. it just shows the charge levels and battery health. unless there is another screen im not getting to.

Unless you are really good with taking a laptop apart, checking those sensetive wires with a meter and have a service manual for the laptop available, it would be a difficult task to perform.

Only suggestion I can give you to preform is opening and closing the laptops cover without actually closing it all the way. If the screen's backlight goes off and does not come back on, you have a problem in the switch which is located in the laptop's hinge.

If the problem is the wiring harness or switch, it is better to have a qualified reputable service person repair the problem.
Laptops are very delicate devices to repair or dissasemble.

It is best left to a professional.

This post has been edited by MrBruce1959: 05 February 2010 - 04:06 PM

actually just tried that. it does turn off before it actually closes and does not return when i hit a button or the touchpad. of course it also does it without touching the lid at all. is this a faullty switch?

Yes, I added that comment when I re-edited my last post to you.

Re-read it.

But what I suggested is to bring it to a qualified reputable service center.

I do not suggest you do the repair or allow a friend to attempt this task, as I know we all let "the kid next door" fix our electronic devices, this time I strongly suggest you take it to a professional laptop service center with an excellent service/repair record.

I will. Thanks a ton for the help. much appreciated!!!

 JQ11, on Feb 5 2010, 04:20 PM, said:

No problem, wish I could do more, but this issue can't be fixed over the net.

Good luck and if you have other issues/problems we're here to help!