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Question

Any ideas on intermittant laptop black screen. HP can't help

Aug 23, 2015 1:02AM PDT

Hi,
I have a problem with my screen going suddenly black. HP have been of no help at all and I’m doing this out of frustration.
I have a:
Pavillion DV6
Product: WF649PA#ABG
DV6-2120TX
The screen is a LG model: LP156WH2 (TL)(Q1)
OS: Windows 32 bit 7 home.

The problem started sometime ago with the screen suddenly going black, it only happened occasionally and then as time passed would do it every few minutes. I could reset it by closing the lid to go to sleep and then logging in again.
I tried an external monitor and it works fine on that when screen goes black.
Shine a torch into black screen and its working away in the blackness.
Did a HP hard reset (battery out & all attached devises unhooked and pressing start button for 1 minute) and worked fine for 2+ days and then started old routine of every few minutes.
Researched problems on the net and come up with Display Inverter problems.
Started to strip screen apart looking for inverter and could not find one, but got the number of screen as above. After more research the net tells me I have a LED screen which does not use an inverter.
HP parts book lists a Display Inverter part # 488317-001 for my model. Now I’m getting confused.

If I don’t have an inverter will it be a faulty screen or something else? Since removing screen yesterday the black screen has settled down and only does it every hour or so.

Any input would be of assistance. Not really keen to upgrade to Win 10 at this stage!!

Discussion is locked

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Clarification Request
There are 3 parts or areas to swap out.
Aug 23, 2015 6:35AM PDT

That could be the LCD, cables to/from and the motherboard. I'm guessing you are looking for which it is but I've seen it be any of the three. This work is usually done at the depot repair since the expense of changing all 3 parts means we buy a new laptop. In the depot we'll can swap one at a time and replace only the failed parts.

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There are 3 parts to swap out
Aug 23, 2015 5:37PM PDT

The laptop is 5 years old and apart from screen blacking out does what I want it to do. Its not worth sending it away to be repaired but if I could pin point the problem I would do it myself.
HP parts and workshop manual says it uses an inverter for the screen but I could not find one. I found a empty space below screen where it should be, but as I have a LED screen and from what I have read on the net LED screens do not require an inverter. Is this correct??
Thanks for your reply

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Took another look around the web. Read this one.
Aug 23, 2015 6:35PM PDT
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Take another look around the web
Aug 23, 2015 7:10PM PDT

Wow thanks for quick reply,
Have looked at Tomsguide before but never came across that post. I will have a look at the wiring.
As for the manual from HP, I've already downloaded that and it shows a inverter. But I haven't got one in computer!! Think the best bet is fiddling with the wiring. Trouble with intermittent problems is you never know unless you find a obvious fault, ie wiring, if you've fixed it or not.
I was hoping I had an inverter as its cheap to replace.
Thanks

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Another look
Aug 23, 2015 7:24PM PDT

Just after posting reply I had a black screen episode. I have a another monitor set up for this and instead of closing laptop lid to reset black screen pressed Fn+f4 to switch to external monitor. Hey presto laptop screen came back to life with login screen. Any ideas where to go from here??
Thanks

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Not really.
Aug 24, 2015 7:48AM PDT

To fix such things we restore to factory condition first. Painful but with all the malware today I've encountered very strange failures that scans don't seem to fix. With the factory condition if it's the drivers, OS or such, then it's back to working condition and the owner is reminded to not tinker with OS, drivers and warned about malware, trojans and their kind.

If the issue is still there it's hardware. But first, HP may or may not have a proper service manual. There has never been a clear mandate or law on that but HP's service manual may be for service techs that know that a LED model won't have this or that. Mostly the service tech needs a guide on disassembly and they will change out boards they think have failed.

Here's where it gets rough on folk. Many expected a full manual with diagnostic trees or more. I haven't seen those in the PC products for over 2 decades.

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Factory restore
Aug 24, 2015 5:57PM PDT

Had been toying with the idea of factory reset for sometime but thought it would be a waste of time with my screen problem. But now I will give it a go at sometime in the future when time permits.
HP got back to me and confirmed that my laptop does not use a display inverter, so you are right about the service/parts manual covering many different models at once and you pick what's relevant to your model. Ha its been an interesting learning curve!!
Many thanks for spending your time on my problem. I will post back when I've done a factory reset and if that has fixed (or not) the issue.