Laptop screen dark problem: Advice plz?

Draeger · 22 Sep 2010 at 15:06

Hi,

I have a friends HP CQ61 Laptop here. His daughter stood on the screen and cracked it so we sourced a brand new replacement. I've fitted this properly but upon starting the laptop after a few times using it over the course of a couple of days the screen went really dark upon its last boot. The screen is working because if you look carefully you can see it but it is as if the backlight isn't working properly. After Googling the issue I bought a new screen inverter for it but no joy - still the same dark screen.

We ended up returning the screen to the supplier in case it was faulty and they sent a new replacement but after fitting it ( and the new inverter ) the same problem is still there. I'm at a loss what to do next?. I have hooked the laptop up to an external monitor and it works fine so I can rule out mobo or GPU issues. I'm wondering if it has something to do with the laptop lid switch?. I can't find an actual physical switch anywhere under the bezel near the hinges but what I did find was a small oblong magnet in the place for the lid switch indicated within the manual. I have no idea how this switch works though?. Any ideas?. I'm really guessing it is something simple that I'm overlooking but I'm banging my head off a brick wall here.

DrBombcrater · 22 Sep 2010 at 20:35

It could be the lid position switch (which may be internal - I've worked on many CQ61s but damned if I can remember where the switch is on them). Also, if the new screen is not an exact match for the original then it may simply not be compatible. Laptops are full of odd incompatibilities, even a screen that has identical specs on paper won't always work correctly.

It could also be that you've got a blown power IC on the motherboard, damaged screens are known to kill them from time to time.

beermonster · 22 Sep 2010 at 21:00

The magnet simply triggers an electronic switch on the bottom half of the laptop, my guess is that the mobo has blown somehow or at best case the cable is damaged maybe whilst swapping the screen.

bees · 22 Sep 2010 at 21:20

could be the video cable as well.

Draeger · 23 Sep 2010 at 09:00

Well, with a bit of judicious fiddling around last night I managed to find the problem at last. Where the video cable clips onto the motherboard at the top left corner, it is secured by means of a sort of "clip" affair underneath. It's a very small clip and easily overlooked. Upon checking closer though, I noticed there was a sort of spring type clip, a tiny one, in the middle of this. I pinched it together with my fingers and it moved inwards slightly. Then I refitted it to the motherboard and rather than just sit there connected, this time it sort of "snapped" into position with a "click" type noise. It now feels much more solid and secure when you wiggle it and lo and behold - the screen came back on and stays on now!.

Excellent!!. Thanks for the pointers folks, appreciate it. :cool: