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My 2009 quad-core MacPro suddenly turned off over night and does not start up anymore. When I try turning it on the graphics card fan immediately spins at full speed. CD and HDs are being initialized. The other fans are running at normal speed. Logic and CPU board LEDs are turned on. I’m not getting a chime on startup nor any picture on the screen. I cannot reach the machine via network either, so it does not seem to boot at all. I tried the usual procedures: PMU Reset, NVRAM reset. Anyone has an idea what’s broken?
It turned out that it was not the CPU but a broken plastic screw that pressed the northbridge’s heat sink against the chip. After putting new thermal grease on the chip and replacing the broken bolt with a screw and a nut the machine turned on again.
Look into the LED diagnostics. If this Answer is helpful please remember to return and mark it Accepted.
