ISight/ wifi antenna causes white screen

devitol

Hi John
I have a MacBook with no signs of water damage but the wifi connector on the logic board causes a white screen when the cable is plugged in. When its unplugged the computer boots normally - minus the wifi. Any secret weapons to fix this?

John

Wow, that's a weird one! No secret weapons, unfortunately. First off, what model machine is it? White A1181, aluminum Pro, etc.? Are you saying the white screen occurs when the cables are unplugged, or when the Airport card is unplugged from the board? I would try replacing the Airport. I would also try holding down "T" or "option" to see if target and option modes come up when the Airport is connected. If they do, that might indicate that the machine is having trouble finding the hard drive (as is often the case with a white screen) and perhaps there is not a video issue. It does sound video-related, though. You can also connect to an external display to see if that works while the screen is white.

Is this a machine that was working, and then it started doing this? If so, what was happening at the exact point in time that the problem began? Hearing more on the machine's history might help.

You might try resetting the PRAM and PMU/SMC, if for no other reason than to say that you did. You might also try reversing the cabling on the Airport card, i.e. connecting the cables to different posts, to see if that makes a difference. If you're using one with three cables, then you have several various configurations to try. Also, try leaving one disconnected, to see if you can isolate the specific cable causing the problem.

Assuming it's a video issue, which it sounds like it is, I can't think of anything other than to start replacing parts -- first the Airport, and then the entire screen assembly, or at the very least the antenna cabling. It sounds like there might be something shorting out the display when the Airport cabling is connected. That's a wild guess, but I don't know how else to explain it. If you've done a screen replacement or had the screen assembly opened up, you might want to go back in and see if anything is crimped/stripped.

Also, when the Airport is installed but the antenna cabling is disconnected, does the machine see the Airport and does the Airport seem to function? Of course you will not be able to connect to a WIFI network with the cabling disconnected, but does the computer recognize the presence of the Airport? If it does, then I suspect the cabling/screen assembly, whereas if it doesn't I'd say it's the Airport itself, or the board (and replacing the Airport will help you determine which of those it is).

Anyway, good luck, and definitely let me know how it goes...I'm very interested to know what's causing this!

Thanks,

John

devitol

Thanks John.
It's a 2009 A1286. The fans also kick on immediately when the computer boots and SMC and PRAM haven't helped. Nor did target mode. I guess I'll start swapping parts.

devitol

John,
Oddly enough it had a bad battery. Once I installed a new batter all symptoms went away. Thanks again for your help troubleshooting...

John

Wow, that's a new one! Glad to hear it's working!