Chosen Solution
Hey guys, I recently got a MacBook pro 17’’ from early 2009. There are no problems to it, if there weren’t those purple lines on the screen. They are not everywhere, only on completely white spots, and they disappear in the area around the mouse-icon. On start up and shutting down, the entire screen turns green for a sec, when it would be supposed to be black. In my eyes there are 3 possibilities. It could be the gpu, the display or some problem with the signal (paths on logic board, or cables). What I tried: When connected to the TV there are no purple lines, while the built in displays shows the lines.When I disconnected the Display and connected the Display from my 15’’ MBP, there where still the same purple lines, so with another working display the problem still occursApplying hard pressure on the housing on the very left between trackpad and keyboard the purple lines disappear temporarilyWhen applying light pressure on the upper/top plastic part of the RAM-Socket also makes the purple lines disappear temporarily until release of pressureTaking out the logic board, cleaning it and fastening or losening the screws of the cooling system on top of the gpu changes nothing My solution so far was gluing some foam on the top/upper plastic of the RAM socket, which applies permanent pressure on the main board and eradicates the purple lines. After googling a lot and looking through a lot of threads here and other places I totally have no Idea what to do. My solution works, but I’d like to have a “real” fix. Display is fine, GPU is fine, so there is something on the mainboard. Can anybody maybe give me some steps what to do, like places to check for on the mainboard, or maybe some link or anything? I’m happy about any help I get, because right now my macbook is shaking a little bit, because of the slight dent. Best regards and thank you for any help, Carl
I’d say you got some issues on the board, but it’s a long way to figure out where exactly. It could be on the way out from the GPU to the connector or somewhere in the Mux circuitry where the switching between graphic cards takes place. In any case it’s probably going to be a long and painful troubleshooting even for a skillful tech as graphics part of the board is packed with a zillion resistors and what not. I’d suggest you try in system preferences to choose the option to always use the high performance graphic card and see if that solves the issue, it might be if it’s Mux related. Good luck :)
