820-3787 Kernel Panic

MacBook Pro has no signs of liquid damage, power on quickly and fine, passes Apple Diagnostics but kernel panics on startup of any OS. The kernel panic is weird though because no kernel extensions are in backtrace, all it says is Thread 0 crashed. I have kind of narrowed this down to being a CPU issue, a PCH issue, or an SMC issue.

However it being the SMC is unlikely, when in SMC bypass mode, the same kernel panic happens, however when I reset the SMC, the OS loads a little bit more then kernel panics.

EDIT: In the image, you cannot really see what's above it too well, but this is where the panic starts, it says at the top: panic (cpu 2 caller): initproc exited -- no exit reason available -- (signal 6, exit status 0)

EDIT 2: Noticing when booting an OS, and it kernel panics, shortly after (15 seconds) it restarts, it will restart again, almost like a kernel panic in the EFI. I also noticed when measuring PPBUS G3H, the voltage is 10.4V, for a 820-3787, is this too high or too low?

EDIT 3: Noticing this seems to be happening when the CPU changes power stages. Would changing U7310,U7320,U7330 stop the panic?

IMG_1146-min.jpg
 
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2informaticos

Administrator
Staff member
Looks like CPU power supply.
You should change the 3 FDMF6808 chips.
Buy new FDMF6708 from serious store.
Do NOT buy "NEW" (refurbished) FDMF6808 chips from China!!!

On Internet are available some software mods, which play with CPU power states.
In some case, you can lose ethernet option; not needed normally.
Be aware, the software mods are not definitive solution.
 
Software Mods are out of the solution, I cant boot into single user mode, or any OS, and EFI bootloader may work though.

I see all these "NEW" FDMF6808 chips on eBay however they are all from China, and another seller that is U.S (laptop-mb-seller) however I have bought some GPU's from him before and they are refurbished used crap.

By serious store, is that an actual store? or did you mean a store like store.rossmanngroup?

EDIT: nevermind, I just bought 6 NEW FDMF6708 chips off Mouser. They had them in stock. I will replace MOSFETs and report back
 
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2informaticos

Administrator
Staff member
Yeah, Mouser, or Digikey.

BTW, some software mods can be done in terminal, before accessing OSX, I suppose...
 
Cant even get to terminal. I suppose you mean Single User mode, however it kernel panics when booting to there too. There is a macOS boot argument (pmsafe_debug) that puts the CPU into a safe power mode, I wonder if this would do anything however I would need to boot into a bootloader to set the NVRAM variable.
 

2informaticos

Administrator
Staff member
You don't need to boot in safe mode for mentioned mode.
Use bootloader and command line.

If the FDMF6708 chips are real new, you may have a problem with GPU; heat it for test...
 
I was already booting off USB, no SSD is connected.

Will try a clean ME.

What else could this be?

EDIT: Used clean latest ME, still same kernel panic.
 
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