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Rich Gable
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No Video on MacBook Pro Display

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I recently bought a MacBook Pro off of eBay that had a liquid spill. I figured this fried the system board (which is fine, i just wanted it for the case anyway). Well, I took out the logic board and followed the steps for reflowing (a.k.a. baking the logic board since i had nothing to lose.) I put the logic board back in and lo, and behold, I got the boot-up chime, but no video. So I plugged it in to an external monitor and it worked great. Well, I obviously wanted to use the laptop without an external monitor, so I took the logic board out of a known good computer (with a beat-up aluminum casing... the reason i wanted to get the MacBook with the fried logic board) and placed it in the new case. Same thing, boot up chime, no video.

Soooo, I figured it was a bad LCD, so I pulled the entire display off of the old MBP (known to be good and working) and put it on the new case. Same thing, boot up chime, no video.

I do know that both laptops are the Mid-2009 MacBook Pro. I know that the old system board was working fine and, as I mentioned previously, the display assembly off of the old unit worked fine.

Would there be ANYTHING that I'm missing here? Can anyone think of why this could be happening? Thanks so much in advance.

Edited by: oldturkey03 ( )

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ABCellars
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With video on the external monitor the video chip producing circuitry is good. I would inspect the socket/header/connector and the area around it for the LVDS/video cable for burn spots or discoloration with a jewelers loupe or stereo microscope. The pins and solder joints on that socket are very small and finding a problem there may be near impossible with the naked eyes. Also inspect the components in the vicinity of the connector for discoloration along with the board and components on the other side of the board in the area almost directly underneath the LVDS header.

Depending on where the board is located at the moment and efficiency either prior to the boards inspection (if the board is currently installed) or after the boards inspection (if the board is out): With the old video cable and old screen hooked up to the new board, no external monitor. turn the system on and take a flashlight or other light source and point it at the screen, look to see if you can find any images on the screen.

Please let us know the results of these things. Good luck.

Thank you for your quick response. I will have to get a magnifying instrument and try inspecting those areas. I did shine a light on screen on boot up to insure that it wasn't just the backlight that was out and there were no images that I could see. I will let you know as soon as I can find some answers. In the mean time, I put the known good display back on the old computer, and it didn't work either. I'm wondering if I just busted something in my haste on both logic boards. :(

Rich Gable,

Better odds of a bad lvds cable.

ABCellars,

If it is in fact the LVDS cable, can those be repaired with ease, or is it best to drop the $80 and spring for a new one?

Rich Gable,

That is an item that needs replaced.

ABCellars,

OK, so a little more information... I brought a known good MacBook Pro home from work, took the screen assembly off and placed it on the MBP that had the liquid damage. The known good screen (with known good LVDS Cable) did not work. So I'm begging to think that the actual connection on the board may have some issues. Are there ANY ways to fix this or is it time to start looking for a replacement logic board?

Rich Gable,

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