MP 1,1-5,1 Help with Mac Pro 5.1 not powering up.

[mandarcy]

Hi,
Does anyone have any clues as to why my Mac Pro 5.1 suddenly will no longer power up? I have tried the SMC reset procedure many many times but nothing. When I plug into the mains I see the red LED flash on the main board and the amber 5v LED will illuminate when the DIAG LED button is pressed so this suggests it is getting power. But when I press the power on button the Mac nothing happens, I do hear a click but no fans spin and there is no other activity. I've tried removing all cards etc but I'm still getting the same results, is there anything else I can try? Many thanks

Kind Regards
Dave

 

[mattspace]

Hi,
Does anyone have any clues as to why my Mac Pro 5.1 suddenly will no longer power up? I have tried the SMC reset procedure many many times but nothing. When I plug into the mains I see the red LED flash on the main board and the amber 5v LED will illuminate when the DIAG LED button is pressed so this suggests it is getting power. But when I press the power on button the Mac nothing happens, I do hear a click but no fans spin and there is no other activity. I've tried removing all cards etc but I'm still getting the same results, is there anything else I can try? Many thanks

Kind Regards
Dave

Pretty sure you need to reset the realtime clock.

From 2009 tech manual, Page 27

Real Time Clock (RTC) Reset

The Real Time Clock (RTC) is a chip on the backplane board that controls the date and time functions of the computer. If the computer is experiencing an issue booting, resetting the RTC may resolve it. Follow these steps to reset the RTC:

1. 1. From the Apple menu, choose Shut Down (or if the computer is not responding, hold the power button until it turns off).
2. Unplug the AC power cord.
3. Remove the battery for at least 20 seconds. You may need to remove a PCI Express card to have access to the battery.

Alternatively, you can reset RTC by pressing the RTC reset button (small button located next to the battery). Press the button for one second when the computer is shut down but still connected to AC power.


FYI : this was an almost miraculous back from the dead for my machine - power outage left one DIMM showing red (and preventing booting when anything was installed in it), then through troubleshooting, it got to the stage where power button would, like yours, make a click, but none of the system fans would spin up (except maybe the power supply fans). Used the reset button and it was all back in business - DIMMs showing correct and everything.

 

[tsialex]

No EFI_DONE LED lit when you press the DIAG button show that you have a non working backplane, that it's not even loading the BootROM.

Could be the PSU not sending 12V, could be a defective CPU tray, could be a corrupt SPI flash memory that stores the BootROM, etc. You need to follow the diagnostic steps from the Apple Technician Guide.

 

[mandarcy]

No EFI_DONE LED lit when you press the DIAG button show that you have a non working backplane, that it's not even loading the BootROM.

Could be the PSU not sending 12V, could be a defective CPU tray, could be a corrupt SPI flash memory that stores the BootROM, etc. You need to follow the diagnostic steps from the Apple Technician Guide.

Hi thanks for the info. The guide I downloaded says to take everything off, drives, opticals, processor, front button and even the wifi and bluetooth cards, and build back up one at a time. I've seen some pics of other boards with multiple buttons for the drag LEDs but my model only has one, whenever I press it, it only ever illuminates the amber 5v LED?

Kind Regards
Dave

 

[tsialex]

Hi thanks for the info. The guide I downloaded says to take everything off, drives, opticals, processor, front button and even the wifi and bluetooth cards, and build back up one at a time. I've seen some pics of other boards with multiple buttons for the drag LEDs but my model only has one, whenever I press it, it only ever illuminates the amber 5v LED?

Kind Regards
Dave

Photos on the guide are for the pre-production boards that have more buttons installed while yours have just the pads.

See page 35, a working Mac Pro should have PSU PWROK (green), 5V STBY (amber), EFI DONE (green), GPU OK (green) LEDs illuminated.

I'd start with a known working PSU.

 

[mandarcy]

Aah, unfortunately I don't have access to another PSU, is there no way to test it to see if its giving outwit it should?

Kind Regards
Dave

 

[tsialex]

Aah, unfortunately I don't have access to another PSU, is there no way to test it to see if its giving outwit it should?

Kind Regards
Dave

Unless you have knowledge + experience and a lot of lab equipment to correctly test your PSU, no. Measuring voltages is not meaningful without load.

 

[mandarcy]

Unless you have knowledge + experience and a lot of lab equipment to correctly test your PSU, no. Measuring voltages is not meaningful without load.

Okay thanks for the info. I think I'll just have to try what the guide says about stripping everything off and seeing if anything happens. If its still the same then I guess its gonna most likely be either the PSU or the backplane? I suppose it would be cheaper to buy a new PSU and try that first?

Kind Regards
Dave

 

[tsialex]

Okay thanks for the info. I think I'll just have to try what the guide says about stripping everything off and seeing if anything happens. If its still the same then I guess its gonna most likely be either the PSU or the backplane? I suppose it would be cheaper to buy a new PSU and try that first?

Kind Regards
Dave

It's cheaper to get a working barebones mid-2010 and use it as a test bed. Then you can sell every working component, and make some money in the process since parts are still very valuable, or buy just what you need to repair yours and sell your test one complete.

 

[mandarcy]

It's cheaper to get a working barebones mid-2010 and use it as a test bed. Then you can sell every working component, and make some money in the process since parts are still very valuable, or buy just what you need to repair yours and sell your test one complete.

That's a great idea, just had a quick look and it seems a full unit isn't much more than some of these individual parts!

Kind Regards
Dave