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I have a Toshiba laptop which has a broken LED screen the screen was broken in transit, therefore you can assume that it was not handled with care. Whilst it was broken it still worked, therefore I purchased a replacement screen.

Now, I have changed a number of laptop screens but never an LED one and noticed that it did not have an inverter but had circuitry taped onto the rear of the monitor which acts as a backlight, therefore only one connector. Great, I swapped over to the new screen powered up, nothing, I swapped it back onto the old screen, still nothing. I did this half a dozen times.

My first thought was that somehow I have knackered both the screens, therefore I took another laptop which had the same screen (Samsung) and connected both the damaged screen and the new one, they both worked perfectly.

Therefore there is something wrong with the Toshiba itself, now could it be coincidence and that the video cable has become dislodged? I doubt it as it was working before I started, could the video card be damaged?

Do you have any suggestions as to what could cause this? I am happy to take the laptop apart if needed, but what should I test?

One other thing, after I had changed the screen the first time and had connected it to an external monitor, I turned the laptop on and the charge indicator stated 85% plugged in not charging which i thought was strange, I decided to remove the power cable and the laptop immediately died as if there was no battery attached, just like pulling the plug on a desktop. I did this twice!, I then removed and replaced the battery re powered and everything was fine 85% plugged in and charging, removed the power cable and the laptop continued to work on battery power.

What may have caused this to happen? Could this be anything to do with the screens not working? Note that the screens were not working before this happened, but could something prior to this when I first connected the battery after changing the screens caused the malfunction of the screens.

Any help or advice would be greatly appreciated

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1 Answer 1

You tested the both the replacement screen and the original screen on another laptop, so you know the screens themselves work fine.

You question whether or not the problem could be the cabling that connects the screen to the motherboard. You did not mention if you checked to see if the cable was properly attached to the motherboard itself. This should be your next step, and it will require you to disassemble the laptop partially, depending on the model of the laptop... like removing the keyboard, and then the narrow panel at the top of the keyboard... or just that panel at the top of the keyboard if the screws that hold it in place don't require the keyboard to be removed. Under that panel should be the video cable connector.

If the laptop was dropped during transit, this could have caused the connector to become dislodged. It could have also affected the battery terminal connections (depending on the severity of the drop) which could explain why the battery was not properly connected/seated until you removed it and put it back in. I'm not saying that the two problems are related necessarily. They could be related simply by the damage (impact?) that caused you to believe the screen was faulty.

The fact that you can connect the laptop to an external monitor is a good indicator that the integrated video chipset is still functioning as it is supposed to.

If you have checked the video cable connection to the motherboard and it is secure, and you have removed and reseated this connector yourself, and you have inspected the cable for any possible damage and find there is none... then the problem may indeed be a motherboard related one. However, I could most definitely check the cable connection to the motherboard and the condition of the entire video cable.

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Thank you i will do that and let you know how i get on. The video cable itself will be difficult to check as the pin outs are tiny, but i will do my best, thanks again. –  Rich May 24 '12 at 20:50
    
@Rich Yes, they are small.. but what you need to look for is damage to the cable itself. unlikely as it may be, the cable may have been pinched at the hinge when it was dropped by the transit company. The motherboard connection itself is more a matter of you disconnecting it, and then reconnecting it firmly. It could have been unseated partially by the impact. –  Bon Gart May 24 '12 at 20:54
    
The thing i should have mentioned, prior to posting was that the laptop had been working fine albeit with a cracked screen, the screen only stopped working after i had changed it, hence me thinking that it may be the cable at the screen end rather than the MB end. Either way i shall take it apart and my Samsung and swap the cables over to test and let you know how i get on. Thanks again. –  Rich May 25 '12 at 14:59
    
@Rich be forewarned, the cable from the other laptop may not fit at the motherboard end. They aren't universal to all laptops. –  Bon Gart May 25 '12 at 16:29
    
Arhhh, that thought had crossed my mind, which means i need to figure out the connectors for both motherboards which is difficult as most system manufactures do not make it common knowledge as to which motherboard model is used. –  Rich May 26 '12 at 8:49

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