Came home today to find my mac unresponsive to my wake commands (mouse or keyboard touch).
I try to restart the computer but am met with the same unresponsiveness.
I do a reset by pulling the mains, pressing the power button for a few seconds and reinserting the power cord.
Same thing.
The power button LEDs would light up but they would die back down after a few seconds.
No other signs of life, no fan, no apple boot chime, no video output signal to the monitor, nothing.
I started by testing the monitor and cables to verify they were working.
I used another computer do this and both worked properly.
I slid off the cover of the Mac and took a quick look around.
The NVME was still a little warm so I popped it out and tried to start the computer.
My thinking was if the HD had died or shorted then it may prevent the system from even booting.
In the absence of a drive or OS the firmware/EFI would kick in and warn that where was no recognizable file structure to be found.
But I was met with the same blank screen, no fan, no sign of life other than the LEDs lighting up.
The power button LEDs let me know that I was getting some power at least.
After a little scurrying on the web I came across the Mac's official service manual along with a few threads on how you could use the built-in LEDs on the I/O board to troubleshoot some issues.
From the photos attached you can see that my #2 and #5 LEDs are a steady green when the system is OFF but plugged in.
This indicates that the system is getting 11V power (#2) and can go into soft power off (#5).
The manual says the #5 LED should be present in all events as long as the system has power.
Then I powered the system on by pushing the power button then pressing/holding the DIAG button to illuminate the LEDs.
This time I got #2, #3, #5 and #8.
LED #3 shows I have 12V power.
LED #8 shows that the system has reached EFI boot.
What I don't have illuminated are:
LED#4 - Platform Reset Release: This indicates that the system has transitioned to a fully running power state.
LED#6 - S0 Power State: This indicates that the SO (full power) state is available.
LED #7 - S4 Power State: This indicates that the S4 (hibernate) state is available.
I didn't get a chance to check the CMOS battery voltage via a testpoint mentioned in the manual as I was going to take the whole thing apart, dust it and change the battery anyway. A few years ago i upgraded the processor to a 12 core IIRC but I dont recall if I changed the battery (probably not). I have read that a bad battery can cause problems but I doubt very much that this is the case here.
My main suspect is the power supply. Its been 10 years since this unit was manufactured and its always ON design means it was powered on (in some state) for all of that time as long as it was plugged into the wall.
I try to restart the computer but am met with the same unresponsiveness.
I do a reset by pulling the mains, pressing the power button for a few seconds and reinserting the power cord.
Same thing.
The power button LEDs would light up but they would die back down after a few seconds.
No other signs of life, no fan, no apple boot chime, no video output signal to the monitor, nothing.
I started by testing the monitor and cables to verify they were working.
I used another computer do this and both worked properly.
I slid off the cover of the Mac and took a quick look around.
The NVME was still a little warm so I popped it out and tried to start the computer.
My thinking was if the HD had died or shorted then it may prevent the system from even booting.
In the absence of a drive or OS the firmware/EFI would kick in and warn that where was no recognizable file structure to be found.
But I was met with the same blank screen, no fan, no sign of life other than the LEDs lighting up.
The power button LEDs let me know that I was getting some power at least.
After a little scurrying on the web I came across the Mac's official service manual along with a few threads on how you could use the built-in LEDs on the I/O board to troubleshoot some issues.
From the photos attached you can see that my #2 and #5 LEDs are a steady green when the system is OFF but plugged in.
This indicates that the system is getting 11V power (#2) and can go into soft power off (#5).
The manual says the #5 LED should be present in all events as long as the system has power.
Then I powered the system on by pushing the power button then pressing/holding the DIAG button to illuminate the LEDs.
This time I got #2, #3, #5 and #8.
LED #3 shows I have 12V power.
LED #8 shows that the system has reached EFI boot.
What I don't have illuminated are:
LED#4 - Platform Reset Release: This indicates that the system has transitioned to a fully running power state.
LED#6 - S0 Power State: This indicates that the SO (full power) state is available.
LED #7 - S4 Power State: This indicates that the S4 (hibernate) state is available.
I didn't get a chance to check the CMOS battery voltage via a testpoint mentioned in the manual as I was going to take the whole thing apart, dust it and change the battery anyway. A few years ago i upgraded the processor to a 12 core IIRC but I dont recall if I changed the battery (probably not). I have read that a bad battery can cause problems but I doubt very much that this is the case here.
My main suspect is the power supply. Its been 10 years since this unit was manufactured and its always ON design means it was powered on (in some state) for all of that time as long as it was plugged into the wall.
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