dual monitors going black!

Question

dual monitors going black!

Hi all,

I have a Mac Pro with an upgraded ATI Radeon HD 5870 graphics card installed (about 2 years ago). I've had no issues at all until recently. About a month ago, I decided to go dual monitor. I have an attached LED Cinema Display (27") via mini displayport, and an older Studio display connected via DVI. I had no trouble at all until 2 days ago. I went to use my computer, and could not get the displays to come on (with a tap of the keyboard). The computer was not asleep. So I did a hard restart (ie, held the power button in until it turned off, then turned it on again), and the monitors came on again. But about 15 minutes into my using the computer, they went black again. I tried unplugging them from the back of the computer and plugging them in again- no luck. So another hard restart, worked ok for about 10-15 minutes, then black. I finally disconnected one of the monitors, and everything seems to be ok for 2 days now. I've tried placing a mini displayport adapter onto the DVI plug, thus giving me two mini displayport monitors- no luck.

There aren't any other issues that I'm aware of (ie, the computer seems to be working fine otherwise). Could this be a video card thing? Any suggestions?

Thanks.

John

Mac Pro 2 x 2.66GHz, Mac OS X (10.7)

Posted on Apr 15, 2013 11:20 AM

Reply

Answer 1

Apr 15, 2013 3:17 PM in response to John Dougherty

Sounds like a Display card thing. Is the card still exhausting air out the grille near the connector? if not, its fan may have died and it couls be overheating.

It might be time to blow the dust out.

Reply

Answer 2

Apr 15, 2013 4:01 PM in response to Grant Bennet-Alder

Thanks for your reply. That's kinda what I was thinking too. But there's hardly any dust in the case, and there seems to be air flowing out of the video card grill. I'm stumped. Are there any utilities which would allow me to see the temperature of the video card?

Reply

Answer 3

Apr 15, 2013 4:06 PM in response to Grant Bennet-Alder

Update: I just gave the fan on the video card a little 'push' and it started up. So I guess there's a short somewhere?

Reply

Answer 4

Apr 15, 2013 5:22 PM in response to John Dougherty

More likely a bad bearing in the fan.

Reply

Answer 5

Apr 16, 2013 10:46 AM in response to Grant Bennet-Alder

Everything seems to be functioning properly (*knocks on wood*). If it were a bearing, is that something that can be replaced with relative ease, or am I in for a new card altogether? Thanks for your help.

Reply

Answer 6

Apr 16, 2013 11:11 AM in response to John Dougherty

The fan assembly would be the field-replaceable unit.

If you can get to the bearing, a drop of light oil like sewing machine oil may give it additional life. [Caution: WD40 is essentially ALL solvent, and will not last long enough to solve this problem.] Grease (even spray-lube grease) is too heavy, and will stop the fan dead in its tracks.

I would approache AMD or the card manufacturer/integrator about fan replacement parts.

Reply

Answer 7

bjbest

Level 1

0 points

Sep 3, 2014 7:27 AM in response to John Dougherty

I had a similar problem. Old mac pro and randomly the monitors would go black.

Replying to this incase anyone else has this problem…

Tried all the restarts under the sun, reset the board only to get temporary fix. It got to the point where the monitors would black out repeatedly after a few minutes of resetting.

My final solution (May not work for everyone): Remove the graphics card and check to see if the copper fins in the heat sink are "caked in dust". On my ATI card i can see this from the bottom end. I took the hoover and placed it at the opening and the bit of the hoover hose that stuck out I covered that with my finger for maximum suction, I repeated this process from the opposite side where the air exits, after a few seconds the suction was enough to clean out the heat sink and the fan started to spin with the power of the suction.

I have replaced the card and now my mac is running very quiet for the first time in years. On removing the graphics card I noticed the bay was very hot including the card. I'm guessing the card cuts out to protect itself from overheating.

Don't forget to wear an anti-static wristband or discharge yourself first. Using a hoover was a drastic last step. Don't think an air duster would solve the problem as well as suction.

Reply

Answer 8

Sep 3, 2014 8:30 AM in response to John Dougherty

I have a small network of brand new macs, 10 of which are the spaceship MacPros. Any machine with dual monitors boots up with digital noise or black and then freezes. I restart, unplug the 2nd monitor, and the machine works. Sometimes it will happen with just one monitor.

16 GB RAM, 3.7 GB Quad core, 10.9.4

Folks are saying it's the OS. Responses on this issue are all over the place, from what I can tell. Wish I had an answer.

Reply