Chosen Solution
Hello dear forum, I ve revived my MacPro 4,1 from the death in my basement. It Starts correctly, chimes and boots in High Sierra but After 2 Minutes / or some load like ‚about this Mac ‚ it freezes and After 1 minute freeze it reboots. Then it has no video no chime no Boot. So Self Test is Not succeeded. If you wait some time And start you get the chime back And it freezes earlier. things i have Tried: all resets (pram and so on) diag leds Show everything ok minimal configuration Changed Power supply to 100% working one Any ideas ? Bad CPU which cause Kernel panic? Please give me your opinions.
best Adrian
Most likely similar to my issue with a 4,1 machine. The Northbridge chip is overheating. Check out this ifixit guide.
