wirefaninpa
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HP DV6915nr display won't light
I have a laptop that has been having problems with the display for months. I can see the images on the screen (especially with a flashlight) but the display is very dim.
At first the problem was that whenever the laptop went into the sleep state the screen would stay dim even when awakened. If I closed the lid and re-opened then the screen would light for a little while. Eventually it stayed lit so long as the computer didn't go to sleep. I stopped the computer from going to sleep at all and this solution worked for a few months.
But now the light has gone out again regardless of the sleep state. When I power on the computer or close and re-open the lid, the display becomes bright for about half a second but that's it. I disassembled the display and couldn't find any loose or untoward connectors. The inverter and everything looks okay. I think the sleep switch is magnetic so I can't mess with that (I have yet to find it). I can't figure out which component is causing the problem so I don't know what to replace.
At first the problem was that whenever the laptop went into the sleep state the screen would stay dim even when awakened. If I closed the lid and re-opened then the screen would light for a little while. Eventually it stayed lit so long as the computer didn't go to sleep. I stopped the computer from going to sleep at all and this solution worked for a few months.
But now the light has gone out again regardless of the sleep state. When I power on the computer or close and re-open the lid, the display becomes bright for about half a second but that's it. I disassembled the display and couldn't find any loose or untoward connectors. The inverter and everything looks okay. I think the sleep switch is magnetic so I can't mess with that (I have yet to find it). I can't figure out which component is causing the problem so I don't know what to replace.
ASKER
Thanks for the feedback BPCC. I have an identical working laptop so I tried switching inverters. The working inverter in the broken laptop made little difference. On bootup the display lit for maybe a second longer than usual, then dimmed as always. Conversely, when I put the inverter from the broken laptop into the working laptop, everything worked fine (in fact, I am typing this message from that laptop using the inverter). Should I try switching LCD screens (assume I would need to try with a new cable, or can I switch those too)? Could it really be the LCD screen?
You said there can be only three reasons, but what about the backlight itself?
You said there can be only three reasons, but what about the backlight itself?
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ASKER
Yeah, changing that will be a real challenge. But I do like a challenge. I'm going to go ahead and try that just for the experience, and if it doesn't work then I will change the lcd display. There isn't any chance that this is a motherboard issue is there? It does seem power-related. I'd rather it not be, but is there any chance that changing the entire LCD display won't fix it?
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switch the whole lcd to test, or dismantle it for swapping the cable (which i suspect) : >>>> When I power on the computer or close and re-open the lid, the display becomes bright for about half a second
another thought : check the lid switch also !!
ASKER
I can't figure out where the LCD switch is on this thing.
If you dont see a button near hinge or protrusion on the LCD panel near the hinges, it could be that that your laptop is using a magnetic switch. As mention by nobus this switch could also be in issue. In the cases with I had experience a faulty switch means no display.
a good help doc :
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00372748&tmp_track_link=ot_faqs/top_issues/en_ru/c00372748/loc:4&lc=en&dlc=ru&cc=ru&product=3740559&lang=ru
download the service manual, and check for it there
http://h10025.www1.hp.com/ewfrf/wc/manualCategory?lc=en&dlc=en&cc=za&lang=en&product=3740559&
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00372748&tmp_track_link=ot_faqs/top_issues/en_ru/c00372748/loc:4&lc=en&dlc=ru&cc=ru&product=3740559&lang=ru
download the service manual, and check for it there
http://h10025.www1.hp.com/ewfrf/wc/manualCategory?lc=en&dlc=en&cc=za&lang=en&product=3740559&
ASKER
After much examination I'm pretty sure this laptop uses a magnetic switch, but I can't figure out where that would be or what it looks like.
it looks like a little black box in most cases, i believe under the right hinge
Just to be sure swap the whole LCD it and test as suggested by nobus.
It will involve some patient work and the test will confirm/rule out if the magnetic switch is the cause to the issue. Really it will make sense to do the swap test before you decide to order CCFL.
It will involve some patient work and the test will confirm/rule out if the magnetic switch is the cause to the issue. Really it will make sense to do the swap test before you decide to order CCFL.
If swapping inverter made that difference I suggest you to swap the LCD. It is easier to dismental LCD and swap than taking the lcd cable out. Magnetic switches never will be an issue. They all had been tested by manufacturer at R&D (Research and Development) stage before they pass it on manufacturing. I will be very surprised actually shocked if its the cause. It would be a design fault too big for HP. Let me know thanks...
Also on one of your comments you mentioned you think its power rlated if you had previous power supply dut off or dead and your battery is not fully charging it would damage the video card. All that CCFL and power related problems are a long shoot. Lets go through the common fault finding process on this kind of instances. Like I mentioned before poer CCFL etc is tested during R7D period actually hammered for consumer do not get that kind faults that easy.
ASKER
It was the backlight; scorched on one end.
ASKER
Thanks everyone. I replaced the backlight and now we're up and running. Not sure that's something I ever want to do again, but it was good for the experience.
I reckon its the inverter.