MP 1,1-5,1 Apple LED Cinema Display - Black Screen

[mechanize]

On Mac Pro startup or restart initially no display (black screen) on Apple LED Cinema 27 Display, have to unplug and plug monitor power socket every-time to make it works and it works fine until I switch off or restart the Mac Pro then I have to unplug and plug the power socket again to make it work !!!

Checked the Mac Pro with other monitor all works OK.
Any idea?

 

[Snow Tiger]

Have you tried to connect the display to another Mac with a mini displayport or displayport to mini displayport adapter to determine if its working fine ?

 

[mechanize]

I have tried Mac Pro with different monitor and all works fine, I will now try cinema display with different Mac Pro and will post...
[automerge]1579006680[/automerge]
OK, I just tried Cinema Display with 2 other Mac Pros, 1 fitted with HD5870 cinema display showing same issue, but when I tried with Mac Pro which has nVidia GT120, it's working fine !!!

 

[Snow Tiger]

Connected to your original Mac , did your Cinema display work fine up until recently ?

 

[mechanize]

Yes

 

[Snow Tiger]

Yes

Connect a different minidisplayport display to your original Mac Pro and determine if your graphics card is failing . If you don't have one available , then try a different interface capable display ( DVI ) . I assume you have a Mac Edition card .

 

[mechanize]

Yes, all mac edition card and I already have tried (non apple) display port monitor (check my comments above) and that monitor is working fine with the MP, I also tried cinema display with other MP and with other MP cinema display is working fine !!!

I think Security Update 2019-007 is causing the problem !!!