Dell Inspiron 5150 - No Screen

I am trying to repair a Dell Inspiron 5150 Laptop. Here's a description of the problem:-

From pressing the power on button the screen lights up dimly although it does not display any boot up info, in fact it displays nothing at all. There is hard drive activity during this process.
Hard drive activity ceases after a minute or so and still the screen displays nothing at all. However, when I attach an external monitor it works perfectly and as soon as I attach the monitor I can see that the laptop has actually booted to Windows and is waiting for me to login. I also need to see the boot up info but this is not displayed on the external monitor as the monitor does not kick in until Windows has started.
I have tried hitting the Fn+F8 key to toggle between LCD/ result!  At first I thought the screen may be dead but I am convinced it is something else, I just don't know what.

Hope someone can help!
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

try gently hitting the pin-button, which sould be somewhere on top of Your keyboard. It may be pushed in, and didn't come out.
It sounds like your backlight or inverter is not working.  I found some information about about some people did to fix it here:
What kind of external monitor is this? I've just had a case of no boot-up (POST) screen on the external monitor, but windows came on nicely. It was caused by this external LCD not being able to accept the VGA output of the POST screen (weird, in my opinion, but that's how it was). Using a CRT monitor helped me there.
Protecting & Securing Your Critical Data

Considering 93 percent of companies file for bankruptcy within 12 months of a disaster that blocked access to their data for 10 days or more, planning for the worst is just smart business. Learn how Acronis Backup integrates security at every stage

in the bios, are there any display initially selector? to select either LCD or CRT?
Wooky JackCommented:
Have you dismantled the laptop itself to see if the monitor is snug on the motherboard?
paulmac110Author Commented:
The Monitor is a 17" ADI Microscan, it only kicks in when Windows is actually loaded so I can't see any information regarding Boot up, I can't even get into the BIOS as pressing all the regular setup keys (F3, F12...e.t.c.) don't seem to work and all I end up with is Windows eventually.
I haven't dismantled the Laptop yet but I think that'll be my next move. It's looking likely that it is the Invertor which has failed.

Anyway, I'll await some more suggestions before replacing the Invertor.


Zuhir ElgmatiApplications and Systems AdministratorCommented:
read this

and i'm so sorry to tell you after i enter to the Dell website and trying to get help from there i enter to the Foums and must Q  like your Q the Answer is the LCD was Dead ....meybe i'm wrong but that what i got ... any way in worst case : to replace the LCD look at this 
Zuhir ElgmatiApplications and Systems AdministratorCommented:
i suggest to enter to the dell Foums ...they have good answers there
If it is the inverter that means you have no backlight. You should then still be able to see the images on the display, just very faintly. Maybe you'll need to look at the display from different angles and with different lighting in the room (if there is too much light you'll probably see nothing). If you can't see any faint images on the display at all your backlight and inverter should be OK, but then you probably have either a broken data cable from the mainboard to the display, or the connector isn't attached properly, or the screen is dead. It should help if you open up the case and wiggle the cables and make sure everything is connected. the data cable for the display can of course break rather easily, as it is inside the hinge and needs to move whenver the lid is opened and closed.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
paulmac110Author Commented:
The backlight is on as the screen gives off a dark gray glow when powered on. I have looked closely at the screen in various lighting conditions and at various angles and I can't see any faint images at all.
I can actually login to Windows by guessing the position of the menu e.t.c (I can hear the Windows login sound). So, I know that the OS system is working fine...but it's no good when you can't see what you're doing!

I don't want to spend money buying a replacement LCD unless I am 99% that it really is the LCD at fault. I'll maybe open the case next and check the cables as Rindi suggests.


It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Laptops Notebooks

From novice to tech pro — start learning today.