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MP 1,1-5,1 Mac Pro5,1 wont boot with 2 monitors attached


macrumors 6502
Original poster
May 4, 2006

Long story short:

My MacPro 5,1 wont boot when both of my 23" Apple Cinema Displays are connected via the stock video card.

If I disconnect one that's using the MiniDisplayPort outlet, it will boot - and I can then re-connect the monitor after it's booted, and it will display on both screens OK.

But if I restart/cold start with both connected again - it stalls at the blank grey screen.

Is this a sign of the video card dying, or the ACD power supply failing, or - ?


Original, longer post:

The other day something tripped our circuit breaker. When I turned it back on, my MacPro5,1 (ATI Radeon HD 5770 card, powering 2 x 2008(?) Apple Cinema Displays) wouldn't start up. It would chime, but then stay on a grey screen (1 screen grey, 1 screen black but with standby light on).

Previously I had experienced the same issue when I had devices connected to the front USB port/s, so I pulled them out and tried to boot again, but still no good.

Tried booting in Safe Mode, but didn't help.

Eventually - clutching at straws - I disconnected the MiniDisplayPort ACD, leaving in the DVI ACD, and again tried Safe Mode. This time it worked - booted into Safe Mode. I then figured I'd try reboot without Safe Mode - and that worked too - still just with 1 screen.

I shut down, swapped the power supplies for the ACDs over - both of them powered the DVI ACD.

Deciding I had nothing to lose, I reconnected the MDP ACD, booted - and all was well again...

For a day, it seemed like it was just a temp glitch... But then today there was some freaky colour issues going on on the MDP monitor. There were some random yellow lines, and sometimes it was like all blue pixels were dancing...!

So I shut the computer down... and restarted. Back to Grey Screen. :(

I danced around again unplugging, plugging in... eventually I disconnected the MDP monitor, started up successfully, then hot-plugged it in. (After verifying that MDP is considered hot-swappable!)

And it is all working again at this moment.

Is all of the above a sign that my ATI Radeon card is dying... or the ACD power supply... or - ??


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