Chosen Solution

Hi all. First time posting here to bear with me if I make any mistakes. I’m used to opening up macbooks and working on them. I’ve owned three macbooks, an imac, and a mac mini over the past seven years so I’m not afraid to repair. I recently bought a macbook, (not my first), for a steal. The seller told me that it restarted itself when opening certain applications such as final cut so I took the chance and bought it. I’ve noticed that it does it when trying to watch a video on youtube, launching certain applications, and other things. It will be working, and then suddenly it completely freezes up, and then after a few seconds, restarts and comes up with the “your computer has restarted because of a problem” line. This would seem to imply a hardware issue or kernel panic. As for diagnosing the problem, I went through a few options before posting on here. I booted up from a clean install on an external HD just to see if it was either the HD or perhaps the HD Sata cable. The problem still came up. For some reason, there is only a 4GB stick of ram in one ram slot. That implies an upgrade/modification by someone as apple installs ram in symettry. When moving the ram to the other slot, I was met with three beeps so I think that slot is bad. I tried other Ram sticks in a series of combinations and i’m still left with only the option of one ram slot. I’ve reset the PRAM and SMC just to check and they had no effect on the computer freezing. I did do a AHT on the macbook and was given the error repot: 4SNS/1/0000008 TC0D–124. I’ve also been given the crash report from restarting which I can post on here if anyone thinks its useful. Either way, I’d love some help trying to diagnose the problem at least, and then I can get to work on fixing it (the part that I’m good at!). Thanks!

At this point I don’t see this as a heat sink issue but without any hard data its anyones guess. This series has a known issue with the HD SATA cable. Even though you wouldn’t think it. A bad cable can cause both the drive & CPU to work harder causing more heat and cause unexpected crashes, I suspect this is a strong likelihood here. If the system is light on memory and the drive doesn’t have much free space on it this can even effect running YouTube vids or other heavy internet function as the drive is often used to spool (cache) the download as it’s playing. So you get a double hit here of the CPU is doing heavy graphics and also dealing with a balking drive which is also heating up things. This SATA cable is quite fragile and if you upgrade the HD you also may find the original cable was not up to supporting SATA III (6.0 Gb/s) drives anyway which is the other shoe to fall here. Your original drive is likely only a SATA II (3.0 Gb/s) drive. Which is why I had asked the question. So the first thing I would do here is replace the SATA cable following this IFIXIT guide: MacBook Pro 13" Unibody Late 2011 Hard Drive Cable Replacement. As to the part I strongly recommend you go with the newer version of the cable here: MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable - Apple P/N 923-0104 In addition I would install a good thermal sensor & fan monitoring app like this one: TG Pro it is by far the best one out there. For less than $20 US its worth it! After installing TP Pro post a screen shot of the main window screen so we can see things. If you enable logging that too could be helpful.

Sounds like overheating issues, download a temp sensor software to verify. Then if it is go around and see if you can replace the thermal paste on the processor and gpu if necessary. If you remove a heatsink you HAVE to reapply, you cant use the old stuff over again.

From adiem48 with identical problem. TG Pro dropdown:

TG Pro main window:

The Platform Controller Hub Die never changes from 43 and wondered if this was cause of error in AHT. The ‘Service Battery’ disappeared when I tried installing Sierra and the battery lasts for hours with low recharge cycle so can’t think this can be cause. Weird 2 virtually identical machines with such identical faults. Thanks for responding. Tony Update (02/17/2017)

Tried to get computer more active without freezing. Best I could do. Tony