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swleo Author

Level 1

4 points

Mac Pro 5,1 boots up without video output

Hi all,

After a restart, my Mac Pro 5,1 boots up without video output, I can access the files and content via a networked computer, so I can confirm booting up is not an issue.

My Mac Pro:

Mac Pro 5,1 (Mid 2012)

3.2GHz Quad-Core Intel Xeon

3 x 16GB 1066Mhz DDR3 ECC

1 x 1TB SATA SSD / 2 x 1TB SATA HD / 1 x 4TB SATA HD

27" Apple LED Cinema Display

I was running on Mojave 10.14.6 with MSI Radeon RX 580 Gaming X 8GB before the error occurred, connect to my 27" Apple LED Cinema Display through HDMI via QGeeM HDMI to Mini DisplayPort adaptor.

The system boots up with the chime with a brief red LED flash on CPU tray.

Methods I have tried:

1. Reset PRAM / NVRAM and SMC

2. Replace PRAM Battery (CR2032)

3. Connect to Samsung Curved LED Monitor (C27F591FD) via HDMI and DisplayPort

4. Connect to Apple LED Cinema Display via DisplayPort to Mini DisplayPort adaptor

5. Replace GPU with MSI Radeon RX 580 Armor 8GB OC

6. Tested both MSI Radeon RX 580 Gaming X 8GB and MSI Radeon RX 580 Armor 8GB OC on my PC - no issues

7. Tested the Apple LED Cinema Display with my PC via DisplayPort to Mini DisplayPort adaptor - no issues

When upgrading to Mojave, I installed the new OS to my 1TB SSD and kept High Sierra 10.13.6 in its original 1TB HD. To make sure my logic board is working, I replaced the GPU with the stock ATI Radeon HD 5770 1GB and boot with High Sierra - everything works fine.

The only thing that I have not tested or replace is the power supply (I do not have the equipment to test), this is a gamble I am not willing to make if I do not know the cause of the issue, was told it was a GPU fault by a technician and bought one, yet doesn't solve the problem.

Kindly seek your advise / insights. Thank you!

Mac Pro, macOS 10.13

Posted on Jul 8, 2020 12:02 AM

Top-ranking reply

Grant Bennet-Alder

Level 10

133,387 points

Posted on Jul 8, 2020 7:04 AM

The display adapters you were using, if accurate, are wonky. Most HDMI adapters can not generate a Mini DisplayPort from an HDMI.

The 27-in Cinema Display has a Mini DisplayPort input.

The card you mentioned appears to have two full-size DisplayPort outputs. You should be using a simple and cheap [full size] DisplayPort adapter from the card to the [mini] DisplayPort input of the display. And there appear to be two different ports to try.

--------

However, to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

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Mac Pro 5,1 boots up without video output

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