Acer 8735G LVDS problem (white lines)

Hi,
A few months ago I had to replace the motherboard of my notebook. Having no graphic card but a HD6650m (with which the notebook display doesn't work) I had no way of testing if the display works.
A couple of days ago I received a GT240m and a HD4670m. I thought I'd try the GT240m first (that was the original card in my notebook). After installing the card and turning on my notebook I was surprised to see that instead of a nice clear image it displayed white vertical lines every other column as if half of an interlaced image was missing.
Thinking that maybe the card was malfunctioning, I replaced the GT240m with the HD4670m. The same image with white vertical lines was displayed.

Does anyone know what's happening? Before breaking my motherboard the display was working fine with a HD4670m. Since I changed the mobo (actually since I got my notebook back from repair ) the display was kept in a plastic bag (to keep it clean) until a couple of days ago when I received the cards. Is it possible that the LVDS cable is broken?

 

Are the lines in the same place every time?

If so the screen or LVDS cable is broken

 

Yes, no matter how many times I insert the card or plug in the LVDS connector the lines are in the same place. The lines are not moving and are not changing color. Here is a picture of an area on the screen that should have been black (all pixels off): http://i50.tinypic.com/2v13mue.jpg
I don't see how the screen could have broken. It was working fine with my previous HD4670m. Is it possible that the damaged card broke the display? How can I check if it's the LVDS cable or the display itself?

 

Make sure the screen cable is also properly seated on the LCD itself.

Also check to see if there are any bent pins on the motherboard LCD cable connector.

BTW I sold the 6650m you were interested in, sorry about that.

...I'm curious to see what happens if you try to boot to windows. I suppose its possible that there is some funny business with motherboard revisions and cables and the timings of the LCD...

 

From power-up to Windows and 3D games (DiRT3), the white lines are still present.

 

Well, you could kill 2 birds with 1 stone, and get a hardware DVI or VGA to LVDS adapter. Then you could use that 6650m I sold you. Probably wouldn't be able to fit it in your laptop or anything, but they aren't very big and I think they're about 40$.

 

This means you think the motherboard is faulty? I have yet to check the LVDS cable and connectors.

 

I really don't know. Actually I suspect there are different motherboard revisions to support different LCDs or something like that.

If you hooked it up to an external monitor with VGA and HDMI with the same issues, then the motherboard would definitely be faulty.

Do you have any other LCDs of the same aspect ratio and backlight type?

Did you get your motherboard repaired?? I think you should take it back.

 

From what I have read any LCD with a resolution above 1280x800 uses dual link LVDS. This notebook was manufactured only with 1600 x 900 and 1920x1080 displays so I think it should support my display (1920x1080).
I am currently using my notebook with an external 4:3 1280x1024 display connected to the VGA output. I works fine, no strange lines. I will check the HDMI output too but I am pretty sure everything is ok with that output.

Does anyone have the pinout of the LVDS 40 pin connector? I would like to check what happens if I remove the clock and data lines on one LVDS channel.

 

The GT 240M appears to be deluded into thinking you have a single-link display.

Try updating your VBIOS. If that doesn't help, post your SBIOS image - it could be an MXM structure issue.

 

I have flashed the GT240m with both the VBIOS of my original GT240m and the latest VBIOS available on Acer's website but the result was the same. I also tried the HD4670m but the white lines are still in place. I though I could be an MXM structure issue so I flashed the SBIOS with the latest available on Acer's website, again, with no result.
Here are my VBIOS and SBIOS: BIOS.rar - 4shared.com - online file sharing and storage - download

I'm thinking it might be a hardware problem but I've checked the LVDS connector on the motherboard and the LVDS cable and connectors.
Here is a picture of the motherboards: P1050527.JPG - 4shared.com - photo sharing - download image The one on top (dark blue) is the old one (broken). The other one is the one I am currently using. The part number is the same.

 

Possibly the 2nd link in your LVDS cable has failed open.

Also, try VBIOSes from TechPowerUp - Acer VBIOSes are not always the most MXM-compliant ones. (I think TPU has an Nvidia OEM VBIOS for the 240M.)

 

The VBIOS and the graphic card are OK. The display is faulty. I replaced it with a 15.6" display and it worked perfectly, just as it did after replacing it with a 17.3" display (LP171WX2). I don't think it can be repaired.
Having no other option but to replace the display, the question is: can I replace it with an LED display of the same size and resolution?

 

Huh? Its not LED in the first place?

I dunno, you'll probably have to find a different cable.

 

It is not LED. It uses two CCFLs. Do you know any 18.4" Acer notebook that uses FullHD LED LCD?