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No image, backlit, w/ with external monitor

Last response: in Laptops & Notebooks
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March 6, 2010 8:28:43 PM

I have a Philips Freevent H12Y. Daughter trod on the screen, still worked in that I could see 90% of the image - I removed the screen (Chi Mei Optoelectronics screen - 20 pin connector ).

I replaced with a LG 20 pin screen which i was assured was compatible. Inverter connected (cant be plugged in the wrong way round) - but now the screen just lights up when I turn it on with no image. When I connect an external monitor I can get a full image, plus when using the F3 key I can turn the laptop screen backlight on/off.

Okay I thought dud screen, so I put the old screen back, but that now shows no image either.

I have checked the cables and connections all look to me as okay.

Question - if the pinout on the LG is different could this have caused this deterioration? Anyone have any suggestions in how the problem could be diagnosed? Or could the new screen have caused damage to mobo which dowsn't affect the graphics to the extent that an external monitor still works?

I know that not all laptop screens are always 100% comaptible in terms of the pinouts (expereinced this with HP), but didn't cause this problem!

Help!
a b D Laptop
March 6, 2010 8:58:23 PM

I don't believe that it has anything to do with the pin layout causing deterioration. It sounds more like a bad inverter. You can probably find one for the particular model around the net on a laptops part site (just google it).
March 6, 2010 9:09:15 PM

Thank you buwish. May I just your advice further.....
I wondered if it was the inverter; am I wrong in thinking that the inverted just provides the power to light the screen? I thought as the screen clearly lights up without an image it was unlikely to be the inverter - as I say I can switch the screen off with the F3 key. Perhaps I need to understand how/what the inverter does? Yr input would be much appreciated, thanks,
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a b D Laptop
March 6, 2010 9:30:53 PM

As far as I know, the backlight and the inverter are two separate parts. The back light simply provides the light (obviously), while the inverter transfers the image from the internal graphics hardware to the screen. In your case it seems like the image isn't being transferred. One way to officially test for this is to hold a flashlight up to the screen while it is on and see if you can see anything.
March 6, 2010 10:57:35 PM

Thanks again buwish................f/u query. Is it possible that the replacement LG screen is not truly compatible with the old Chi mei screen and therefore if I get another inverter the new screen could burn out/damage the inverter again?
Anonymous
a b D Laptop
November 3, 2012 7:37:06 PM

I am sorry but the inverter provide high voltage to the backlight and it has nothing to do with the image tranfered from the motherboard to the screen lcd matrix.
So don't buy another inverter because your is fine.
If your replacement screen wasn't compatible with the original one the only thing that could happened there is either you bended or damaged the connectors in some way when you tried to conect the replacement or it was a shortcut in the process and now the motherboard doesn't provide the 12volt needed for the screen matrix to work. If you have a multimeter in house you can check if you have 12volt on the connector that is going to the screen. You can identify which pin you need to check by looking after a very small SMD fuse on the screen board. That is your 12volt line you need to check.
!