2 
1 What is the purpose of the small ribbon cable, bottom left?
I had a little beer spill on my MacBook Pro this afternoon. Immediately shut down, pulled the battery. Took it apart to clean the components, but found no beer had escaped the left speaker (maybe a little under the keys in the top left—if they get sticky, I'll pull apart and throughly clean the keyboard).
During disassembly, I damaged the connector for the tiny ribbon cable that attaches at the very bottom left of the board (as looking at the upside down machine), near the hard drive connection. The machine boots and behaves normally, except with some bizarre video artifacts when there is dark shading of a certain gradient (in which case, those pixels are a shimmering bright green).
What is the purpose of that cable (which appears to go to the hard drive, so I'm thinking it's a temperature sensor for the drive, or something along those lines. Just trying to figure out if not having it connected is responsible for the video artifacts, or if that's a completely separate issue.
Thanks!
Is this a good question?
3 Comments
Can you locate the cable in the teardown guides? What color is it?
by mayer
I figured it out...it's for the white power indicator LED on the front edge of the computer. I guess I can live without that working. Certainly live with that a lot easier than replacing an $800 logic board! I wonder if a tiny dab of CA (glue) and lining it up jussssst right might fix things...
Now to figure out what's up with the video being all wonky...
by Jamie Rasmussen
I verified that it's not the graphics chip, as plugging in an external display results in a perfect picture (no crazy Moiré patterns, like on the built-in display).
By swapping solid color background images, I've determined that the green Moiré patterns appear wherever a pixel is true black. It looks for all the world like a video connection issue, but I've inspected the video cable and connector on the logic board, but there is no readily apparent damage. Reseating it and ensuring it's firmly in place also has no discernible effect.
by Jamie Rasmussen