MP 1,1-5,1 Mac Pro 5,1 turns on on ac plug, no chime, no video, no keyboard power

[luissuma]

Hi everyone!

I have a mid 2010 A1289 Mac Pro 5,1

It turns on. Front, rear, psu and gpu fans spin slowly, both optical drive and hdd spin on turn on, but there is no chime, no video and no power to keyboard, so resetting PRAM is not possible.

If diag button pressed, PSU PWROK (Green), 5V STBY (Yellow), EFI DONE (Green), GPU OK (Green).

I removed the backup battery to reset the Real Time Clock chip, and after doing this, the computers turns on automatically when plugged in ( as in power-on on ac back configuration).

Tried apple’s suggested minimum configuration test. When turned on without processor, processor red light illuminates. And it goes off when processor is installed back. The dimm leds never illuminate, whether dimms are installed or not.

Has anyone seen these symptoms before? Any help appreciated.

 

[Whipmaker]

Had this with Power supply on 2 previous 2010 MP's

 

[luissuma]

Had this with Power supply on 2 previous 2010 MP's

Hi! Thank you for your reply. Just wondering, did you have the automatic turn on when plugged in as well? Just curious because I have not read about that specific symptom in any other thread.

 

[tsialex]

automatic turn on when plugged in

You can set the RTC to power on automatically when the power is restored.

 

[Whipmaker]

I recall one did the auto power-on the moment I connected the cable,(a upgraded to nvme drive and 3.46 cpu with flashed 680) the other required me to press the power button 3 or 4 times to get it to turn on initially but once it did it behaved( and still does) quite normally.
Both PSU's were sourced via amazon as Brand New(no idea if they actually were but both are still working 4 years later)

 

[Whipmaker]

Worth noting is that both had theSPI bios/efi chip replaced about 2 years before, it was done preventativly rather than because of any problem (work was slow and I was bored and the devil makes work for idle hands) but yea power supply

 

[Macschrauber]

When the rtc battery is low or missing the Mac Pro starts with plugging in.

 

[luissuma]

When the rtc battery is low or missing the Mac Pro starts with plugging in.

Thank you for the information!

 

[luissuma]

Turns out it was the CPU board. Bought another Mac Pro, same year/configuration and swapped the cpu trays and it worked. Swapped only ram and processor and it worked. But when I tested the cpu board with the ram and processors that were working on the other machine, the issue returned. Hope this helps anyone in the same situation.

 

[Macschrauber]

Have you tried swapping the batteries?

 

[luissuma]

Have you tried swapping the batteries?

I did, that was my first guess, but after doing it the issue remained. Turns out it was the CPU board.