Mac mini mid 2011 random reboot

[Scorpion2782]

I bought a Mac Mini mid 2011 and sometimes i have an hard reboot. I thought it was a power problem and I replaced it but nothing seems to have changed.

If i execute log show --predicate 'eventMessage contains "Previous shutdown cause"' --last 1h the result is kernel: (AppleSMC) Previous shutdown cause: -128

I searched online but i cannot find anything.

Any suggestion?

 

[Audit13]

Does the reboot happen consistently with a program, website, or some other process?

Could be a ram problem. Try running the free version of memtest: https://www.memtest86.com/download.htm

Could be a problem with the boot drive.

 

[iluvmacs99]

I bought a Mac Mini mid 2011 and sometimes i have an hard reboot. I thought it was a power problem and I replaced it but nothing seems to have changed.

If i execute log show --predicate 'eventMessage contains "Previous shutdown cause"' --last 1h the result is kernel: (AppleSMC) Previous shutdown cause: -128

I searched online but i cannot find anything.

Any suggestion?

Do you have any USB devices attached to the Mini? If you do, disconnect all of the devices except your mouse and keyboard. Then reboot and see if you see a hard reboot. If you do, then exchange the USB keyboard with another keyboard to see if you see a hard reboot.

When you have defective USB devices or an underpowered USB hub, it will cause the Mini to crash or reboot. I have the same mini as yours, so I am speaking from experience. I had a defective USB hub that crashed my mini and I had a defective USB keyboard that did the same. If none of the USB devices are causing the reboot, then check your boot drive. It could be failing or else it is close to full and are having problems page swapping due to limited RAM on your mini. You should have at least 20% of free space on your main boot drive reserved for page swapping.

Hope this helps.

 

[hobowankenobi]

Safe Mode would help isolate third party software/extensions.

Booting to an external drive would isolate the internal drive, OS, software, and associated components (like SATA cable).

 

[Scorpion2782]

Ram checked, usb checked (i need to try with bluetooth keyboard), thermal paste replaced but the result is the same: reboot and shutdown cause -128.
Sometimes after this reboot the screen still black and the fan is loudly

 

[hobowankenobi]

Have you ruled out software/OS? Booting to external would also test SATA bus/cable.

RAM can pass all tests and still be problematic, as can a bad RAM slot. I would try one stick at time you is can:

test 1: RAM 1 in slot 1
test 2: RAM 1 in slot 2
test 3: RAM 2 in slot 1
test 4: RAM 2 in slot 2

If any of the above is stable...you have a winner. If none of the above works, either it is not RAM....or possibly both sticks are bad. Unlikely, but possible.

 

[Scorpion2782]

what i don't understand is why sometimes when i reboot so the screen stays completely black, nothing happens and the fan starts at maximum

 

[Scorpion2782]

could it be the fan that is shorting? I read a little online that sometimes the temperature sensor is in the fan