Possibly a mystery Mac Mini story

N

nucircle

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Mac Mini Intel Core 2 Duo 1.83GHz, no hardware changes since purhcased, a year and 4 months ago. OS 10.5.6. I come back to the office and it's frozen. When I try to restart, it gets stuck on the grey apple screen (no wheel underneath either). I did the following:

• Disconnected all peripherals
• Reset PRAM
• Reset SMU (I even tried the PMU reset, which results in the fan spinning at max speed)
• Holding the option key correctly invokes boot disk options, but no choice works (as explained next)
• Tried booting up from DVD
• Tried booting up from external firewire drive
• Set it in target mode and verified via firewire that the internal drive is working fine (I checked it with Disk Utility with no errors found and even booted up from it). In this mode even the DVD in the Mini's drive showed up on the other computer's desktop and it's perfectly bootable
• Reseated the RAM
• Replaced the RAM
• Booting in single-user mode ends up here: http://nucircle.com/mini.JPG
• Tried to restore firmware, but no-go (DVD spins up but no progress)
• Disconnected internal HD to force other boot-up disks to engage
• Tried another power supply from an identical model
• Re-applied 10.5.6 update in target mode
• Ran hardware test - everything checks out fine

Before I contemplate more drastic measure (like retiring it), is there anything I haven't done? I appreciate any help.
 
Look like the CPU based upon reading the errors generated in single user mode. I know many of the Intel Minis had issues with Hynix RAM with one or both chips consistently failing. If the replacement RAM you tried was Hynix RAM, I'd try another brand and retest just to be safe. There is a slight possibility it could be the interconnect board not fully seated to the board or the extremely delicate ribbon cable connector broken on the interconnect board, so I'd double check those connections. If the Mini was pretty caked with filth inside when initially taken apart (have seen this often) could just be the heat buildup cooked the CPU.
 
djackmac, thank you so much for the prompt reply. I suspect the CPU more than the RAM. The one currently used is the original Apple set. When I replaced it, I used another original Apple set, which I know it was working in another identical Mini. No filth in there when I opened it (unlike some other machines I have...). I reseated the board several times, I made sure everything was connected properly. If it is the CPU, is there an economical way to replace it? If so, any tutorial around? Many thanks.
 
The hardware test, ideally, needs to be run in "looped" mode... sometimes a single pass won't reveal an underlying problem.

Try running it looped and let it test over and over for a good hour or so. See if any error messages pop up after that.
 
nucircle said:
One thought: wouldn't the hardware test indicate a faulty CPU?
Click to expand...

I rarely see failures running the Apple Service Diagnostics only available to ASPs on bad logic boards or CPUs unless it is an obvious thing like a shot GPU showing bad video fragmenting/distortion. Like EDCC said you would be better off trying to loop it several times to build up heat and possibly see a failure, but sometimes even then I won't see a failure.
 
Thanks to you both. I have been running the test more than an hour and no errors whatsoever. That means little, from what I understand. Any suggestion, besides the obvious "trash it!", is most welcome.
 
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