Cinema Display going blank on Mac Pro

Hi folks... I have a 2010 vintage (pre-thunderbolt) Mac Pro & LED Cinema Display. The LED Cinema Display is going blank intermittently and randomly. This is the 2nd LED Display that is having this problem and Apple had provided a new one to me as a replacement about 6-months ago. Although it's possible, I'm finding it hard to believe that I received (2) LED Displays that have the same problem, that have gone through Apple's quality / production system.

It could be the monitor board, but I've also had the Mac Pro looked at (4) times for a hard drive issue and the system scan has come out clean each time.

When the LED Cinema Display is lit, everything works like a champ.

I also have an Apple TV where I can play music from the Mac Pro in the living room. However, whenever the Display goes blank, the Apple TV will show that it's lost it's connection and can't play music for the entire duration that the Display is out. As soon as it comes back on, the Apple TV works great again.

Thoughts?

Thanks,
Paras.

tikku22 said:

Although it's possible, I'm finding it hard to believe that I received (2) LED Displays that have the same problem, that have gone through Apple's quality / production system.

It could be the monitor board, but I've also had the Mac Pro looked at (4) times for a hard drive issue and the system scan has come out clean each time.

Click to expand...

Well...if as you say you don't believe that 2 displays could have the same problem...and the Mac Pro has been "scanned" (whatever that means)...there's really not much left (it's got to be one of those two things)....the computer or the display!

I agree with you...if I had to guess...the displays are probably not the issue...it's probably the Mac Pro. And more specifically the video card. No 100% guarantees...just guessing based on the info so far.

This can be be confirmed in one of two ways:

1. Plug that LED display into a 2nd computer (Macintosh or Windows computer)...if it works fine...then the problem lies somewhere with the Mac Pro. If the monitor flickers...then it's the display.

2. Plug a different monitor into the Mac Pro. If this 2nd monitor (not the LED monitor) flickers like the LED monitor...then it's the Mac Pro. If this other display does not flicker...then it was the LED monitor that was the problem.

If you don't have a 2nd monitor or a 2nd computer to troubleshoot with...then you're going to have to go to the Apple Store to have them figure it out.

- Nick

Thanks, Nick... the problem is that it happens only intermittently.

I have an 2006 MBP, but the Display has a mini-DVI, so I don't have an ability to swap the computer out; I can try the Mac Pro on our TV, so I'll post results of that.

I don't know the system scanning that the Apple Store had done, perhaps someone on the board here could enlighten us with some details; but they had found no problems with the Mac Pro, including the video card. Yet, they swapped out the video card anyway... after (4) months of dragging the almost 100 lbs of Mac Pro + Display to the Apple Store, they couldn't reproduce the problem with the Cinema Display, and eventually just gave me another Cinema Display (this one)... Needless to say, I'm not keen on going thru all that again. Also, the new Pro's and Display have Thunderbolt, so it's not like I could go swap everything so easily.

Is there anyway to diagnose this at home... is there a system scan software or debugging software or places I can go to in the OS that I could use to see / record what's going on? Kind of like the computer in a car? As I say, I do not want to bring this thing back in to Apple.

Thanks,
Paras.

tikku22 said:

Thanks, Nick... the problem is that it happens only intermittently.

I have an 2006 MBP, but the Display has a mini-DVI, so I don't have an ability to swap the computer out; I can try the Mac Pro on our TV, so I'll post results of that.

Click to expand...

Let's look at things this way. The Mac Pro is a couple years old...and you've tried TWO basically brand new LED "Thunderbolt" displays in the last 6 months.

So of these two (the computer or the monitors) which one is more likely to be the problem...my guess would be the computer (and more specifically the video card). So by plugging your Mac Pro into what I'm assuming is a perfectly operational TV...this should provide you with some valuable info.

If after you plug your TV into the Mac Pro...you get the intermittent display problem...then you know that the problem is the computer (possibly the video card). Of course you will have to leave your Mac Pro hooked up to the TV long enough for the intermittent problem to have a chance of showing up (you wouldn't want to unplug the computer form the TV too soon).

If you don't get the problem after plugging the computer into the TV...I'm thinking three possibilities:

1. The Mac Pro wasn't plugged into the TV long enough for the problem to show up.
2. The TWO LED displays must have been defective.
3. There's some sort of unknown incompatibility between a 2010 Mac Pro & the new Thunderbolt displays.

- Nick

OK.. thanks...

I hooked up the Mac Pro to the TV via a mini-DVI to HDMI converter adapter and, indeed, the TV video and sound are going out intermittently. So, the problem must be the video card in the Mac Pro or the motherboard. I don't have spares of these to swap out, any way to find out?

Thanks, Nick!
Paras.

tikku22 said:

So, the problem must be the video card in the Mac Pro or the motherboard. I don't have spares of these to swap out, any way to find out?

Click to expand...

More than likely it's the video card...but there's really not a 100% for sure way of knowing without having a 2nd video card to test with. You're only having video problems...that's why the symptoms would indicate the video card.

But...before you go out and buy a video card...open up your Mac Pro...remove the video card...and then reinstall it. Just to make sure it didn't get knocked loose or something...and to be sure it's seated properly.

If you still have video issues after doing this...then I would say that it's time for a new video card. From time to time video cards on Mac Pros go bad...so it's not unheard of.

For what it's worth. Since you have a 2010 Mac Pro...I'm pretty sure you can use a GeForce GT 120 video card. This is a low-end card that shipped with 2009 Mac Pro's...and used they can be found on e-Bay (sometimes) for under $50 bucks.

That's VERY inexpensive...and might be a good card to get if you REALLY wanted to test things out before paying "bigger bucks" for a better card (unless the GT 120 will get the job done for you).

- Nick

tikku22 said:

I also have an Apple TV where I can play music from the Mac Pro in the living room. However, whenever the Display goes blank, the Apple TV will show that it's lost it's connection and can't play music for the entire duration that the Display is out. As soon as it comes back on, the Apple TV works great again.

Click to expand...

I was rereading things...and noticed that you mentioned that the sound "cuts-out" as well when you loose the display signal. This may complicate things a bit...since it's possible to lose video without losing audio.

I'm still thinking the video card is the best next place to troubleshoot. The video card is MUCH easier & cheaper to troubleshoot/replace...and considering that replacing the logic board would be a MUCM MUCH more expensive proposition (and a pretty tough job to replace as well).

- Nick