Chosen Solution
I am troubleshooting a Macbook Pro. It is a 13". I think it is the late 2012 model, but I don’t have it on me for refernce right now and I don’t think it is relevant. I have alot of experience with computers but not alot with macs so I just want to see if I have overlooked something stupid. I’m pretty sure the motherboard is fried. It will not boot. I tried holding d while booting to run the hardware test. This starts but then hangs partway through and eventually the computer turns off. I tried reinstalling the os both through the network and through a bootable usb but neither option works. I can select the proper drive but then the laptop shuts down again. Also at certain points when I have tried to boot up I get a folder with a question mark instead of a mac symbol. Also once I got a kernal panic which said something about memory. I should have written it down because I could not replicate it. I know it is not the hdd or the ram. I know this because I removed them both one at a time and put them in a different MBP, where they worked just fine. Also I took the working hdd and ram from the second MBP and put them, one at a time in the malfunctioning one. Nothing worked. So what I want to know is this: Is the motherboard fried? Or have I missed something. Thanks.
This is a well known issue. Apple even replaced it for free for about six months. The Hard drive I/R cable gets damaged as it comes over the last 90 degree bend and onto the optical drive. I also put electrical tape on the rough bottom surface to prevent vibrations from the hard drive rubbing the cable. Also I place 3M extreme mounting tape on either side of the cable (red tape) to prevent the bottom case from contacting it. If it booting OK from your external drive, just replace the cable: MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement
A good place to start with issues such as you mention, is to reset your PRAM (NVRAM) and SMC. You can find instructions on how to do that here and here. Then give it a try. You should do this when ever you are changing out parts. What kind of charge does the battery have? What color is the Magsafe (charger) LED and is it bright or dim? What are the last 4 characters of the serial number - to help us confirm exactly what MacBook this is. Has this been dropped or exposed to liquid?
i think your right, Needs A mother bord or has hard drive issue. I would guess mother bord.
