MBP 15" will not stay on while assembled

Discussion in 'MacBook Pro' started by Ranfanman, Aug 7, 2011.

  1. Ranfanman macrumors newbie

    Aug 7, 2011
    Hello everyone, I've been driven here by desperation. I seem to be having a fairly unique problem with my computer. It is a MBP 15", 2.16ghz core 2 duo, early-pre 2008 model. Let me tell you the sordid tale of how my beloved old workhorse came to be a partially assembled, half-functional mess of a machine on my kitchen table.

    I am a student. Not wanting to shell out for a brand new MBP as my major required, I decided to go the cheap route and give my existing computer a few upgrades at a fraction of the cost. I ordered 2gb of RAM and a 750gb WD Scorpio black hard drive. I am not the most technically savvy when it comes to hardware, so I enlisted the help of my brother, an IT consultant, for installation. Even he had never dared to crack open an MBP, though, so we were both new to the process. Armed with screwdrivers and guides, we set to work.

    The RAM doesn't bear mentioning; I did that myself the day before without problems. The hard drive installation itself, though lengthy and frustrating, was also completed without significant trouble. The problems really began during the reassembly process. We put everything back together, screws and all, and tried to boot the computer. Nothing. Disassembled everything again, thinking the ribbon cable connecting the top plate to the mobo was loose. It was, so we retaped it and tried again. Nothing. More tape to hold it in place, and did not screw down or snap in the top plate. Success! Computer booted properly and ran the snow leopard Installer. We shut it down then and reattached everything before trying to boot again. Nothing. after an hour or so of wrestling it we got it to boot while open again, and decided to go ahead and install the OS. That went off without a hitch, so, case still open, we restored my files overnight from an external drive. Now all that is left to do is to close the computer. This is the main problem.

    The computer starts reliably if the front plate is completely detached or the right side is completely snapped in. However, in the half-attached state, any pressure on the unattached side will kill the computer. If both sides are snapped in, the computer will not start. I have, with careful pressure, managed to narrow down the detached portion to the top left corner, where the power cord enters. Shame on me for working on a device that's still on, I know. Based on what I've seen after much tinkering, I have come up with two possibilities:
    -The ribbon cable connector is still somehow coming loose when the case is fully assembled or is damaged from our repairs (it has been fiddled with a lot by now)
    -there is something wrong with the power supply, or something making contact where it should not when the case is assembled

    The first of these seems the most likely, as adjusting that tiny connector has gotten us to the point of being able to boot at all. However, I am still in the dark about how to resolve this. Keep in mind that we have a fully functional computer here - only when disassembled. I am writing this on the iPhone that mercifully arrived right before starting this project , but this will not do for when classes start in a few weeks. Any insight into keeping the ribbon cable connector secure or other advice would be much appreciated.
  2. Detrius macrumors 68000

    Sep 10, 2008
    Asheville, NC
    The fact that pressure kills the computer implies that something is either shorting out or getting disconnected, and that corner points to the Left IO board. Check the ribbon cable that connects the LIO board to the logic board. It's near where the hard drive connects and has black felt on top. Unplug it, and make sure its leads haven't come separated from the cable, and then plug it back in.

    Additionally, using something static-safe and non-conductive (a "black stick" or nylon probe tool), poke around and see if there's anything specific that kills the computer when it's touched. For data safety, you can unplug the hard drive cable and leave the computer at the gray screen with the blinking question mark while you probe.

    Since it happens without the screws, it's not likely anything is getting shorted out. Since it happens with pressure, it's more likely that something has a faulty connection. It's unlikely that the top case itself is relevant. You should be able to duplicate the issue with the top case leaning against the LCD (but plugged in for ease of power-on).

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