2018 Mac Mini Constant Reboot

[Bl0ckHe1d]

Hi all,

Seeking help for the Mac currently running on the latest MacOS software which is constantly rebooting and greeted with the following pictures then it reboots again showing the same messages in the pictures. I am using the logi-tech IR keyboard therefore not sure if I can get the Mac into Safe mode (or any other modes for that matter!).

Any assistance or advise how to rectify this would be greatly appreciated

 

[Bl0ckHe1d]

Ok, little progress, was able to get the Mac into Recovery Mode and got as far as the Utility Page then it reboots again.

Now I cannot get the Mac into recovery mode, every time the Mac is switched on it will display the Apple Logo and the White LED is illuminated, then the Mac reboots again (LED is now off), this process repeats over and over!

Update, LED comes on, now no Apple Logo, then LED goes off again, repeat!

Can only hazard a guess that the power supply unit is goosed, or worse, the motherboard?!

 

[Fishrrman]

Is the RAM inside as it came from the factory?

Or...
Did you change it at some point?

 

[Bl0ckHe1d]

Is the RAM inside as it came from the factory?

Or...
Did you change it at some point?

Changed the RAM a few years ago from 8gb to 32gb

 

[Fishrrman]

"Changed the RAM a few years ago from 8gb to 32gb"

Then... take the 3rd-party RAM OUT, and put the factory-installed RAM back in.
See if that makes a difference.
(yes, I realize it's a bit of work)

 

[Bl0ckHe1d]

"Changed the RAM a few years ago from 8gb to 32gb"

Then... take the 3rd-party RAM OUT, and put the factory-installed RAM back in.
See if that makes a difference.
(yes, I realize it's a bit of work)

Will happily try anything to get this Mac going again! Changed the RAM back to the factory-installed RAM, sadly still the same result.

LED will come on for 10secs, no Apple Logo, then LED goes back off again for about 8secs then repeat.

 

[opeter]

The problem is either with the soldered SSD or something with the logic board or any of the integrated component (like the T2 chip, etc.)

The only option, that I can think of, is to try to change/swap out the CMOS battery and see if there is any change.
https://www.ifixit.com/Guide/Mac+mini+Late+2018+Disassembly/115396 (look at step 11).

 

[Fishrrman]

OP:

Get a WIRED keyboard.

Try booting while holding down the shift key (safe boot).

Try booting to INTERNET recovery:
Command-OPTION-R

No promises. Just worth trying. But again, get a different keyboard.

 

[Bl0ckHe1d]

OP:

Get a WIRED keyboard.

Try booting while holding down the shift key (safe boot).

Try booting to INTERNET recovery:
Command-OPTION-R

No promises. Just worth trying. But again, get a different keyboard.

Many thanks Fishrrman, the wired keyboard with Command-Option-R now brought up the internet recovery but the holding down the Shift didn't work.

1. Out of the power-up power-down cycle;
2. Now in a starting internet recovery (this may take a while) loop each reboot approx 2mins, would I be correct to assume that this constant rebooting in internet recovery mode is normal and just let the process continue?

 

[opeter]

Leave it for a few hours. If the internet recovery doesn't work or finished, there's a (physical) problem with the machine.

 

[Bl0ckHe1d]

Took the mini to the Apple Store to see if they could resolve the issue, preliminary diagnostic suggests that the Thermal Interface Module (TIM) has failed. They’re going to run a deeper diagnostic on the mini however the Tech is 90% certain that the motherboard will need replacing!

Replacing the motherboard would be in the region of approximately £465 with a 90days warranty 😳

 

[Bl0ckHe1d]

Another update, a full diagnostic is completed and has only returned one issue which is the Thermal Interface Module.

The tech has managed to install macOS Catalina and is ready for collection. The tech isn’t sure or cannot guarantee how successful this will be before it sh!ts the bed. So will collect the MAC tomorrow and give it the benefit of the doubt and see how it goes…