Back Light or Inverter Diagnosis

Hello all,

First time poster here, but not a forum newbie. So, hopefully I provide enough information to get a few educated responses.

I have an older Compaq Presario V2570NR laptop. I shut it down the other evening and everything was well.

The next morning I was going to check my email. I usually turn it on and walk away and wait a minute or so for it boot up to the login screen. When I came back to log in the screen was blank.

I could barely see the login screen. If I squinted my eyes and angled the screen just right I could faintly see the login screen.

So, I then plugged the laptop into an external monitor via VGA cord. Perfect screen. So, at that point I eliminated the video card for sure.

I also know that the LCD screen itself is fine. Since I can faintly see the login screen. There are no cracks or anything in it as well. Also, if I shine a flash light on the screen I can see the login screen a little better.

From the research I have done this points to one of two failed components. Either the backlight or the inverter.

I would also like to mention that when the laptop first boots up and shows the Compaq logo the screen flickers once quickly and has color. It will also flicker after I login and my xfce4 session is loading.

Would this point to the backlight still being good and the inverter is what is bad?

I would like to pinpoint the issue so I do not have order two parts when only one is needed or order the wrong part when it was the other.

Any and all help is appreciated! I tried to explain thoroughly enough, but if you need more information let me know!

 

Hello and welcome to the forums. You probably looked this up on Google already.

http://www.google.com/search?hl=en&q=how+to+test+laptop+inverter

It says that the inverter is most likely the culprit and it's a lot easier to replace than the backlight.

 

you rebooted? one of my laptops did it irregularily, and rebooting always helped. the only thing that sucked was, when it was out of sleep not illuminating anymore. thats when i learned hibernate to love... reboot without losing your saves

 

Anyways till you figure it out consider an external monitor or HDTV and a cable to connect to those (VGA cable) if you have important info on your laptop that you have to access everyday.

 

I had the same issue.
It turned out the back light in my LCD went out.

If the image turns black and you only see a very faint trace of it on the screen, then the likeliest possibility is that the back light is responsible and needs to be replaced.

If your laptop is under warranty, I recommend you send it to your manufacturer for repairs.
If it's not, then simply take it to a nearest repair shop and have it fixed.

Getting the replacement parts if you are doing it on your own might be tricky.
I think that ebay would prove to be of great use to you for this particular aspect.
Make sure you find the back light that can be used in your laptop though.

 

I have already found the back light and inverter OEM replacement for under $60.00 a piece minus shipping online.

I am confident in doing the repair myself rather than pay inflated prices for parts and labor at repair shop...

Still trying to nail down the culprit.

 

You may want to do a dry run and remove top deck plate and front screen bezel. If you get through this without mishap, look around for the cables for the inverter and from main board. Reseat and inspect. The cable through a hinge should be looked at carefuly as this is a wear point.

You can pull and test the inverter if your handy with wires; http://www.fonerbooks.com/laptop14.htm

Good luck

 

I would also say its the inverter. It would seem a lot more likely for the inverter to fail rather than the backlight.

 

Yes, I have removed the screen bezel and top deck. Removed and reconnected the inverter and checked all the wiring to inverter and through hinges. I did not find anything out of place or a worn wire or anything like that. I will take a look at the link you provided and see where that takes me. I will report back with an update.

Thanks!

 

Well, my Craftsman multimeter does not have Hz read out on it. So, that is a dead end

 

i have an old vaio which does this. when i open the screen and close it a few times after it gets to the login the screen the backlight usually comes back on. i cant think why but it now works normally after a system restore so i have no idea what was wrong there