MacMini8,1 (2018) Showing blinking STOP sign

[ee91137]

I've bought recently off eBay a MacMini8,1 2018 but it shows a blinking STOP sign on boot...
Tryed Diagnostics, Recovery mode, Revive under DFU Mode, etc ... nothing seems to work.
The nands are TSB 3232 U87535 JPNA1 ... how to find capacity of each nand?
From the markings of the T2 Chip is it possible to know if its 1GB or 2GB ?
If blink STOP sign is caused by faulty SSD where can I buy replacement nand chips?
Board has 639-06007 as model... corresponds to which configuration?
Thanks

 

[Nermal]

Does booting with Cmd-V held down do anything different?

 

[ee91137]

Hi Nermal,
Tried Cmd-V and nothing different ... plugged a Ethernet cable on it and tried Shift +Cmd + Option + R and nothing

 

[bzgnyc2]

I've bought recently off eBay a MacMini8,1 2018 but it shows a blinking STOP sign on boot...
Tryed Diagnostics, Recovery mode, Revive under DFU Mode, etc ... nothing seems to work.
The nands are TSB 3232 U87535 JPNA1 ... how to find capacity of each nand?
From the markings of the T2 Chip is it possible to know if its 1GB or 2GB ?
If blink STOP sign is caused by faulty SSD where can I buy replacement nand chips?
Board has 639-06007 as model... corresponds to which configuration?
Thanks

What happens if you hold down Option to get the Startup Manager?

Mac startup key combinations - Apple Support

Learn about the Mac features and tools that you can access by holding down one or more keys during startup.

support.apple.com

If you can't even get to Startup Manager, I suspect the issue is hardware as my understanding is that Intel Macs can normally bootup even with no working internal disk.

When you say you tried Diagnostics, did it not work at all or did it just say Passed despite not otherwise booting?

Then have you resetting the NVRAM/PRAM?

If you can get to the Startup Manager, have you tried booting of an external disk (e.g. USB installer)?

 

[ee91137]

What happens if you hold down Option to get the Startup Manager?

Mac startup key combinations - Apple Support

Learn about the Mac features and tools that you can access by holding down one or more keys during startup.

support.apple.com

If you can't even get to Startup Manager, I suspect the issue is hardware as my understanding is that Intel Macs can normally bootup even with no working internal disk.

When you say you tried Diagnostics, did it not work at all or did it just say Passed despite not otherwise booting?

Then have you resetting the NVRAM/PRAM?

If you can get to the Startup Manager, have you tried booting of an external disk (e.g. USB installer)?

Holding down Option gives no result ...
Tried resetting NVRAM and gives no result/no chime.
I'm unable to see anything on screen than a blinking STOP sign ...
I've tried D for diagnosis , Shift+Cmd+Option+R, Cmd+Option+R, T, etc ...
As those MacMini8,1 have T2 ship, I'm unable to go to boot manager.

I'm able to launch machine in DFU mode and connect to a Apple Configurator 2...
He successfully do revive and restore and MacMini8,1 reboots but then again blink STOP sign.

Called local apple official repair shop. I was told they only do diagnostics on full assembled original parts machines.
As I bought only pcb, they don't even diagnostic.

 

[bzgnyc2]

Holding down Option gives no result ...
Tried resetting NVRAM and gives no result/no chime.
I'm unable to see anything on screen than a blinking STOP sign ...
I've tried D for diagnosis , Shift+Cmd+Option+R, Cmd+Option+R, T, etc ...

Have you tried Option-D to pull the diagnostic utility from over the internet? Speaking of internet, do you have wired Internet available or were you planning to use wireless?

Also what kind of keyboard are you using and how is it connected? I am sensing your keyboard combinations aren't even being seen by the system.

As those MacMini8,1 have T2 ship, I'm unable to go to boot manager.

Note the Startup Manager is available on T2 macs. Though by default, Startup Security is set to now allow booting from external or removable media. You can change that in Recovery Mode but of course need to get to Recovery Mode for that to be useful. If the internal SSD is not working and you can't get internet recovery working, you could be stuck in a catch-22.

I'm able to launch machine in DFU mode and connect to a Apple Configurator 2...

It may be possible to change Startup Security or other relevant settings from Apple Configurator but someone else would be better to advise on that...

 

[ee91137]

I just took a thermal camera picture on two MacMini8,1 boards, the one with blinking STOP sign gives abnormal heat signature under the air cooler. So probably is a malfunction chip/component on the board.
The good board has only a little heat spot on the Aquantia Ethernet 10Gbit controller.

 

[ee91137]

Just made a video of yhe hest signature:

Broadcom and thunderbolt controllers are hot ...
No short detected at thunderbolt ports.
Little metal debris was found between Broadcom pins.

 

[bzgnyc2]

Perhaps you can share a little more context -- did you buy this machine "as-is" or "parts-only" or did the original seller claim it was working? Are you trying to revive this computer for sport or because you need a working Intel-based Mac?

Then if you are looking for help debugging hardware faults, there are probably better forums than "Mac Basics, Help and Buying Advice".

As far as isolating the issue, I would lookup the boot sequence for T2 Macs and specifically how the handoff happens from T2 to Intel chip. Also whether the video is always driven from the Intel side. I would think if it gets this far (enough to drive video and display the 'things are bad' graphic), at least the main (Intel) processor has to be working. Then while I am guessing the T2 drives the DFU and related, I would be surprised if they let you update the firmware via Configurator if the main chip was inaccessible. Also since you mentioned the SSD is likely not original, I'd look up the experiences of those who hardware hack these things and what they had to do to pair new drives and see if any of the error messages rhyme with what you are seeing.

If the issue is hardware failure other than RAM or similar, it is unlikely to be worth repairing from an economic efficiency perspective. You can buy a like new Mac Mini 2018 i7 ~ $300.

 

[ee91137]

Perhaps you can share a little more context -- did you buy this machine "as-is" or "parts-only" or did the original seller claim it was working? Are you trying to revive this computer for sport or because you need a working Intel-based Mac?

Yes I bought it already knowing it had STOP blinking sign.
I'm doing studies without scholarship so buying cheap and try fix can help support sone projects, Arduino, CAD design, home server, etc ...

Then if you are looking for help debugging hardware faults, there are probably better forums than "Mac Basics, Help and Buying Advice".

Thanks

As far as isolating the issue, I would lookup the boot sequence for T2 Macs and specifically how the handoff happens from T2 to Intel chip. Also whether the video is always driven from the Intel side. I would think if it gets this far (enough to drive video and display the 'things are bad' graphic), at least the main (Intel) processor has to be working.

👍

Then while I am guessing the T2 drives the DFU and related, I would be surprised if they let you update the firmware via Configurator if the main chip was inaccessible.

👍

Also since you mentioned the SSD is likely not original, I'd look up the experiences of those who hardware hack these things and what they had to do to pair new drives and see if any of the error messages rhyme with what you are seeing.

I'm sorry but SSD is original...
I've just refered the SSD markings TSB 3232 U87535 JPNA1 as for someone to find nand capacity.
AI from Google says each chip its 256GB, total 1Tb.

If the issue is hardware failure other than RAM or similar, it is unlikely to be worth repairing from an economic efficiency perspective. You can buy a like new Mac Mini 2018 i7 ~ $300.

I'm trying to repair cheap as possible to be able to use machine.

 

[ee91137]

Today thermal analysis suggests the problem is related to SR40E Peripheral Controller Host...
It showed some marked area around four capacitors on top and chip gets hot upon startup: