iMac stuck during booting from any HD, recovery mode, safe mode, etc.
Hi guys and gals!
I'm having issues with my late 2012 iMac 27" (EMC 2456) with an 3,2 GHz i5 CPU and the GTX 680 2GB.
What doesnt work:
- The iMac does not boot but gets stuck on the gray screen with the apple logo and the horizontal progress bar. The bar stucks at the same position every time.
- It boots neither from the new SSD nor the old SSD, nor any USB device, nor the Recovery Partition, nor into Safe Mode, nor can I install Mac OS through the Internet.
What I tried so far:
- Reseting PRAM/NVRAM (Command-Option-P-R)
- Booting into Safe Mode (holding Shift) doesnt work
- Diagnostic (holding D) works but even the detailed search didnt indicate a hardware fault
- Removed the RAM, restarted and got the alert from the logic board
Kernel Panic Log:
panic(cpu 2 caller 0xffffff7f8f04ed7a): "bool IOAccelDisplayMachine2::display_mode_did_change(uint32_t): vendor driver returns false"@/BuildRoot/Library/Caches/com.apple.xbs/Sources/IOAcceleratorFamily_kexts/IOAcceleratorFamily-378.18.1/Kext2/IOAccelDisplayMachine.cpp:490
Backtrace (CPU 2), Frame : Return Address
Kernel Extensions in backtrace:
BSD process name corresponding to current thread: WindowServer
Mac OS version:
Darwin Kernel Version 17.5.0: Mon Mar 5 22:24:32 PST 2018; root:xnu-4570.51.1~1/RELEASE_X86_64
Kernel UUID: 1B55340B-0B14-3026-8A47-1E139DB63DA3
Kernel slide: 0x000000000de00000
Kernel text base: 0xffffff800e000000
__HIB text base: 0xffffff800df00000
System model name: iMac13,2 (Mac-FC02E91DDD3FA6A4)
What I did prior to the crash:
2 years ago I deleted the fusion drive respectively split it into SSD and standard HD (just mention it in case its relevant for someone)
Yesterday I cut open the iMac and replaced the standard HD with a SSD (Samsung EVO 860 1 TB)
To avoid the fan running to high, I put an Thermostat from OWC (OWCDIDIMacHDD12 Inline-Digital-Thermo-Sensor) between the board and the drive
Did not put in new adhesive stripes yet but fastened the display with duct tape because I first wanted to check whether everything works.
Installed High Sierra through internet on the new SSD.
Whilst performing the migration assistant the monitor turned black.
Reopened the Mac. Disconnected and reconnected the 2 display connectors to the board. The display worked again and I finished installation (this time without the migration assistant).
After about 5 hours of installing, downloading stuff etc. I got a kernel panic.
The iMac then booted neither from the new SSD nor the old SSD, or any USB device. Not even the Recovery Partition.
I opened the Mac and noticed a mellow smell like burned circuit but could not locate that smell. My wife could not smell it so I though I might be wrong.
Next day, I removed the OWC thermostat. The Mac booted again from both disks and seemed to work fine again for a while.
After about 2 hours however I got the kernel panic screen again. I opened the iMac again and I though I smelt something burned again.
Any suggestions on how to proceed would be highly appreciated!
(Edited: editorial changes and kernel panic log)
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