Chosen Solution
Tonight I made a second attempt to install a different logic board into a MacBook Core Duo that I’ve been working on. For background on this undertaking, see the details outlined in my question regarding the first attempt. I’m having the same issues as before, even with this second logic board, but I’ve noticed this time that the fan is working and the screen does indeed display that reassuring instantaneous white flash upon depressing the power button. So, I’m convinced the display is working properly. However, even with all the internals operating correctly, when powered on, the sleep light immediately lights up and remains lit and when resetting the PMU, no tone is heard after the sleep light flickers, which is unusual. What I’m wondering now, is if what I need to do is to completely erase the hard drive I’m booting with in order for the MacBook to boot up? Will this possibly solve the issue? I’ve tried booting from an install disc, but the optical drive won’t read the disc and it ends up holding the disc hostage until I extract it by taking the drive apart. I’m thinking about attempting to boot from my MacBook Pro via target disk mode to avoid this issue, but I’m not sure how well that would work. Other than that, I’ve wondered if disconnecting and reconnecting the PRAM battery could help get me anywhere. I feel like I’ve tried everything and haven’t gotten very far. Thanks again for your help, reliable and wise iFixIt community. Update 11/25/10 After switching out the RAM cards I’d been using throughout the whole process with an older set from the original computer, I was able to get the MacBook to fully boot the OS from the hard drive with all the data intact and problem free. For some reason however, when powered on, the “system can’t locate a startup volume” question mark folder flashes once before going to the Apple logo and booting up. I’ve heard from people and Apple Geniuses that this means that something is wrong, but I’m unsure of what. It doesn’t seem to be causing any software issues. The only problem I am having now though is that the keyboard and trackpad on the top case are completely unresponsive, even thought the power button works. Any suggestions on how to fix this issue would be greatly appreciated. Thanks!
It’s not sounding like a hard drive problem. In fact, you shouldn’t need a hard drive in the computer at all to do this level of testing – I’d remove it and all the rest of the extraneous peripherals (battery, extra RAM) until the computer starts behaving. With the hard drive missing, your goal is to get to a white screen with a folder and a blinking question mark. Try booting in option mode (hold down the option key while booting up) and target mode…do either of those modes work? If so, that’s a good sign. If not, I’d connect to an external display and see if you get anything…if you see something on the external display, you know the problem is in the screen hardware and/or related connections. But with the symptoms you describe, I doubt option or target mode or an external display will be working. But if target mode does work, then yes, definitely try booting up to your other computer’s drive, and boot that computer up from this computer’s drive, again, if it’s possible to do. The PRAM battery thing has never been a solution that’s worked for me. Especially since the board you have is new, you should definitely not have to be doing something like that. You may want to try a different topcase. An Apple store may have one in the back that you can plug in briefly to see if that’s the problem. I’ve seen bad topcases cause strange issues that can keep a machine in a hung state. Sounds like the PMU is resetting (flickering light)…but with no tone, are you sure you’ve plugged the speakers back in? Can you hear a tone via headphones? If so, the problem is in the audio hardware (speakers, cabling, etc.), and not on the board. Could be a RAM issue. I’d test known good RAM, one slot at a time leaving the other slot empty (in case you have a bad slot). I’ve definitely seen a few RAM issues causing a MacBook to behave like you’re describing.
I had the same problem before after a logic board replacement. I’d tried resetting the PMU and PRAM but still no dice. I don’t know why or how it worked, but I removed the battery, pressed the power button for 8 seconds, attached the charger cord and booted. The darned thing then booted normally. Shut it down, reattached the battery, and everything came up dandy.
erasing the hard drive shouldnt do anything. You could try to stick the start up disk in and reboot it from there. Update i would try booting it from your other computer and if that doesnt work then there is something else wrong with the mac. Update dude i just read what you posted in the first attempt and i would get a new hard drive cause i would guarantee you that that one is ruined because of the coffee.
