Acer 5742 replacing screen

[shanksy]

Hi all,
I know there are some good techies on this site so I thought I'd post my plea for advice here :

I am fixing my sisters laptop at the moment (Acer 5742), problem was that the screen had gone, however if you shone a bright light on it, you could faintly see the display, therefore just the backlighting seemed to be the problem.

I have stripped the laptop down and could find nothing wrong with the lvds cable connector or any of the connections, and as the screen is an LED backlit LCD there is no inverter (i believe) to check either.

So I ordered a replacement screen and have subsequently fitted it. Now the screen is completely dead, there doesn't appear to be power going to it at all. Laptop still runs fine on external monitor, but only boots into windows when external is connected.
I have tried reconnecting the old screen and this is now completely dead also.

So it would appear that I have disturbed something (which I cannot find) or there is another step I have missed in replacing the screen.

Basically I'm all out of ideas now and have until Monday to decide whether to return the new screen without incurring restocking fees.

Any ideas?

 

[John]

Hmm, that is a bit odd.

I can only think the display connector on the motherboard is iffy. It can't be the graphics card because you get an output to an external monitor and as it is working, it's not the motherboard per se either.

Perhaps one or more of the pins has a broken track up to it or is loose?

If it is trying to repair that is going to be tricky as I would think you'd need to get the motherboard out to see the underside - unless you can get to it from underneath. Replacing the MB may be cost-prohibitive and might be worth selling with a knackered screen - and putting the money from sale, what you would have spent on a replacement MB and the cash you get back for the display - towards the next one...

Behold the number of screws if you try and dig further!

That's very poor for what would seem to be a fairly young laptop.

Is it used as a portable or does it remain in one place (just thinking external as a more permanent option)?

 

[shanksy]

Thanks for the reply mate,
Yes it is a bit shoddy considering how young the laptop is. Unfortunately leaving in situ and hooking up an external monitor is not an option so its either a fix, or a return of the new screen and selling it on with the dead screen.

The MB is about the only thing I haven't removed yet, I have the back, front, keyboard DVD, HDD, screen and ram all out. Doesn't look like a problem to get to the underside, I just don't know what to check when I get there.

The display connector on the MB looks OK, its a shame I don't have another lvds cable to test really.

Is there any way I can check the voltages with a multimeter, I'm not sure how to check without frying circuitry!

Cheers

Hmm, that is a bit odd.

I can only think the display connector on the motherboard is iffy. It can't be the graphics card because you get an output to an external monitor and as it is working, it's not the motherboard per se either.

Perhaps one or more of the pins has a broken track up to it or is loose?

If it is trying to repair that is going to be tricky as I would think you'd need to get the motherboard out to see the underside - unless you can get to it from underneath. Replacing the MB may be cost-prohibitive and might be worth selling with a knackered screen - and putting the money from sale, what you would have spent on a replacement MB and the cash you get back for the display - towards the next one...

Behold the number of screws if you try and dig further!

That's very poor for what would seem to be a fairly young laptop.

Is it used as a portable or does it remain in one place (just thinking external as a more permanent option)?

 

[shanksy]

Solved!
Just stripped down and built back up again and the old screen worked as before without the backlight, tried the new screen and now works perfectly.
I'm wondering if the screen cable was being pulled out when I closed the lid or something.

I can sleep properly now!