I just had the power supply replaced because I had no power and it was bad. Now when I start up all I get is a black screen! I am using the same monitors connected the same way as before. The strange thing is that at the shop where the power supply was replaced it starts up with the proper image -- they can't find anything wrong. I am Baffled!!! I need some HELP!!! Thanks in advance. Harold
[Edited by Moderator]
Mac Pro, macOS 10.15
There may be some difference in replacing that 3 Volt BR2032 or CR2032 coin cell battery.
But the most common symptom when the battery is spent is that, especially after being off power (i.e., unplugged to get it home from the shop) you press the power button and it does not even turn the fans completely on.
but are you connecting to the same ports they connected to in the shop?
I have seen a MacPro graphics port go bad, but the rest of the card worked FINE. I added an adapter to a different port and I was back in business.
The simplest thing your Mac can do to show a default picture on the display is to start up in Startup Manager, whose code is all in ROM, and no drives need to be working to get the display to work.
Hold Option at startup, and it will, over the course of several minutes, draw a gray screen, then add an Icon for every potentially bootable drive it discovers.
provided you can get something, it can be changed to a setting that works for your display
Then the output port of the graphics card, your display, or its cabling has likely failed.
Does the display have "on-screen display" settings you could look at to see if IT thinks it can draw something?
Yes the display has on-screen display and when I start up the Mac Pro the on-screen display just goes black. The display also tells me if it is getting a signal and it is. The whole thing just gets more baffling!!! How can I be experiencing what I am and yet the shop gets an image which I saw???
About the only thing i could add to this post, small as it maybe , is to replace the Pram/Cmos battery on the backplane, it’s behind the video/graphics card, it usually lasts 5 years, official replacement is a BR-2032, which may be hard to find, a CR-2032 will work fine. I presume you have done this already : https://www.macworld.com/article/224955/how-to-reset-a-macs-nvram-pram-and-smc.html.. follow the part for Intel Macs… as Grant Bennett-Alder mentioned, either try a different video/graphics output, maybe a different cable and see what that does, otherwise, suspect a bad graphics card, check out the mac pro technician guide available at http://tim.id.au , go to “Laptops” section.
hope this helps a bit
John B
I have tried twice to start up in startup manager, waited about 20 minutes each time, but still get just a black screen.
Bad cable, or bad monitor, or maybe a monitor or controller that has lost its display resolution settings.
Or bring it all into the shop, monitors and cables and all.
Mac Pro screen stuck on black screen
