Resolved 2011 MBP boots and shuts down

[martinocando]

It has been working fine for the past months, just a few weeks ago started with an issue with the volume indicator, that was showing by itself. A bit annoying, but it fixed itself after a couple days. Then 2 days ago, it simply shut down, and when I press the power button, it boots to the login screen, but I can't even type in the password. It shuts down right away.
Then it won't even boot for quite a while. more than an hour sometimes. Then it has the same behavior.

This is a 2011 13 inch MBP with 16GB of RAM, that I installed a year ago, and has been working eventless so far. I also replaced the HD at that moment with a Samsung EVO Pro 256GB. No issues with it either.

So far, I've tried the following:

• Booted in recovery mode, and just selecting disk utility, shuts down
• Reset PRAM
• Booted with Command S, it shows some messages in a Terminal like interface, and shuts down after a few seconds
• I booted in safe mode, and was able to enter the password, but shut down right away
• Thinking it might be the CPU overheating, and having Arctic Silver 5 laying around from a recent PS4 repair, I dismantled it and replaced the CPU paste. I even cleaned and prepared the surfaces with cleaner and purifier solutions that came with the AS5. I've done that before, extensively, so I know what I'm doing. After the thermal paste replacement, it behaves exactly the same way.
• I also booted it up with the battery disconnected, and it did exactly the same thing

BTW, when I was replacing the thermal paste, I saw another smaller heatsink covering maybe the chipset. Should I have that paste replaced too?

The battery indicator shows 8 solid green dots. The Magsafe is green too. Today after the termal paste replacement, it turned red for half an hour or so, and while I was doing something else, waiting for it to charge, I heard the startup chime a couple times, but it didn't booted.

Do you think the battery might be dying or is dead?

I'm really desperate, and I ran out of options. This is my daughter's computer, and she have a Thesis to finalize. There is a recent time machine backup, so we are not so worried about the data, but the machine itself. I can't afford to replace it until December.

BTW, I don't live in the US, so going to the genius bar is out of the question. There is no such thing here, sadly.

 

[Pineapples23]

i had somethign similar. if you could go to the apple store for help, which i know you can't. they may say its a kernel panic with problems with the motherboard and needs replacement, and even replacing clould be like 400 dollars american

 

[yukari]

It could be your RAM. Yes they do go bad. Simplest way to determine if it's a bad RAM is to put your old RAM back in and see if the problem persists.

 

[martinocando]

Ok, I think I found the cause of the issue. Is the fan not spinning up. With the back cover open, I turn the computer on, and I can see the fan rotating, but at normal silent speed. Not roaring when is supposed to.
An hour ago, I replaced the thermal paste again, just for the sake of doing something, and I forgot to connect the trackpad ribbon cable.
So I booted it up, with the USB installer, and this time I could hear the fan at full speed. I didn't hear it before. I didn't finished installing, because the USB was bad, so I created a new installer USB, but turned off the computer.
Turned it on again, this time I plugged the ribbon cable, and the fan is back to near idle speed, and it shuts down. I'm pretty sure is overheating, and it shuts down the computer to protect the CPU.

Since I forgot to connect the trackpad ribbon cable the first time, for a moment I though that it might have been the trackpad causing some kind of short circuit that impeded the fan from spinning up, so I unplugged it and tried again, but still the fan was not spinning up.

So, do you think it might be the actual fan failing, or is there a sensor I need to check? Can it be the heat sink too? Any other ideas?

Thanks for the help

 

[martinocando]

It tuned out to be the trackpad. As I mentioned, my daughter had an issue with the trackpad a few months ago, but since it fixed by itself, we forgot about it, but I should have ordered a replacement, knowing what was coming. The trackpad have what they call a Palm Rest Thermal Sensor, that maybe was giving the computer a wrong reading. For protection, the system shuts down the computer to avoid damage, but is very hard to troubleshoot, unless you work for iFixIt, which was the site that immediately went to the solution, by just reading the symptoms.

So, I took the trackpad apart, brushed it off with a toothbrush and rubbing alcohol, making sure to reach all the crevices, and wherever I can see some dust buildup, and put it back. Immediately the computer started working normally. So, I will order a new trackpad, and will also order a new SATA cable, which is known to have issues with this particular series of MBPs.

Thankfully the computer didn't got any more serious damage.