PDA

View Full Version : Can't get LED 24" CD to work properly with MBA Rev B




habbakuk
Mar 18, 2010, 05:56 AM
To make a long story short, I've been to the Apple store multiple times, on the phone with AppleCare multiple times, and am sitting in front of my second 24" LED Cinema Display. Neither mine nor my wife's MBA Rev B (both 1.8 SSD, 10.6.2, new CD firmware) could properly drive either monitor without the screen "glitching" (improper synchronization, resulting in horizontal shifts of chunks of pixels for a fraction of a second). I've read a bunch of posts, and it seems that a number of other users encounter this problem, maybe calling it "occasional flicker?" This flicker happens every few minutes at this point, making it more than "occasional," and, quite frankly, unacceptable. Additionally, the entire display with just go black for a fraction of a second, though this happens maybe once an hour or so.

I've done all the usual things (reset the SMC, PRAM), and I've driven projectors (MiniDisplay -> VGA or MiniDisplay -> DVI) from this laptop without incident. The monitor is plugged into a SmartUPS 750, so the power is as clean as can be. It doesn't matter whether I run it in clamshell or open modes, with/without the bluetooth keyboard/mouse. It doesn't depend on the load - it will happen running heavy MATLAB computations, or just reading e-mail.

Also, since resetting the SMC, when I run the MBA in clamshell mode, and I disconnect the MagSafe connector from the laptop, it immediately puts the computer to sleep; this is actually handy, as it saves me a step, but it didn't used to happen - what happens on your MBA/LED CD when you disconnect?

Any suggestions/thoughts to continue to troubleshoot would be appreciated. Thanks!



jns2001
Mar 18, 2010, 08:08 AM
I have a rev.C, whenever your are driving an external monitor and you disconnect power it shuts off. Have you tried starting it with the shell closed?

habbakuk
Mar 18, 2010, 08:44 AM
I have a rev.C, whenever your are driving an external monitor and you disconnect power it shuts off. Have you tried starting it with the shell closed?

I'm not sure what you mean by "starting it with the shell closed?" When I run it with the shell closed, I follow the manual and plug everything in with the shell open, close the shell, and then wake from sleep with my bluetooth keyboard/mouse. I have also tried plugging everything in while the MBA is closed, which wakes it from sleep. The flicker problems persist either way. Is there a different way to start it with the shell closed?

stoconnell
Mar 18, 2010, 09:33 AM
I think that you have to adjust your Power Saving preferences while on battery. Resetting PRAM/SMC reset several of the system settings to factory defaults, which is not too surprising.

I am able to drive a 24" Dell monitor at 1920x1200 using MDP->DVI adapter from Monoprice in clamshell mode while connected to power with no screen issues. I use a USB keyboard with mouse (I dislike the idea of dealing with batteries for the bluetooth peripherals) hooked up to the USB hub in the monitor (along with several other peripherals). I did make a power setting change to not put the display to sleep (ever) while on power to avoid having the laptop go to sleep when keyboard and mouse go away due to the USB hub shutting down with the monitor. I typically suspend my machine (close the lid on battery), connect to power, USB and monitor and then turn on the monitor and hit the space bar.

Make sure when you are connected to the monitor that you are not blocking the vents since you lose the keyboard surface as an additional way to dissipate heat.

habbakuk
Mar 18, 2010, 09:41 AM
I have a 24" Dell (1920x1200) at work that I just tried to drive today with the MDP-> DVI adapter; it works beautifully, with no sync issues.
I've tried to play a bit with the settings stoconnell mentioned; it doesn't seem to matter whether the display is set to sleep or whether it is set to remain on forever. The computer stays quite cool to the touch, unless I'm running something processor intensive, and the vents are not blocked. I've tried elevating the computer a bit above the desktop, as well, but there's no indication that it is overheating.

Scottsdale
Mar 18, 2010, 10:20 AM
You mentioned seeing the flickering when doing anything from email to other apps, but I want to know do you have multiple apps running or just the email app running?

Do you have the settings properly set in the system preferences for energy savings? I wonder if the "automatically reduce brightness before display goes to sleep" box is checked? If it is, deselect it. In addition, do you have it set for power adapter to ensure computer sleep and display sleep are set to a longer period of time? Actually, can you set both to an hour or more and test?

Next, how about the heat. Does it do this more when you first startup your MBA or when your MBA has been running for several hours? Where do you set your MBA in relation to the ACD? Are there any other power draining devices near either? The UPS you have, can you remove that completely and just plug your ACD into one power strip with nothing else draining power from the same outlet? Try that and see if there's a difference.

Do you ensure that the power cable is not twisted around mini display port cable when separating the cable to send power to left side and mini display port and USB cable to the right side? Can you ensure that the cable coming out of the ACD isn't pulled or stretched to the MBA. Also ensure that the cable is lying flat on desktop and when it splits into three cables the power is going to the left side straight from the main cable without wrapping around the mini display port cable. Can you ensure that the mini display port cable is pushed in correctly and it's not being tugged on or stretched in any way. Basically, think about ensuring that the cables aren't twisted and seem to naturally flow straight to their targeted ports on the desk.

I don't know the answer to the following, but could you try it. What if you just plug the ACD's mini display port and USB cables into the MBA. Then, use your MBA's power adaptor to power the MBA instead of connecting the ACD's power cable for the MBA. If you do that, do you get the same results? I have an idea as to why this is happening, but I don't know whether it works or not. I don't have my ACD in front of me, but if I did I would check this out.

Can you not run Safari or FireFox while you're seeing the flickering? Run any other apps other than a web browser and see if it flickers. Only use one app at a time and see if you still get flickers. Leave all other apps closed... not just minimized to the dock but not open. Just boot computer and open one app and see if the display flickers. If it only happens while Safari, or another browser is running as the active program, or in the background, remove all third-party plug-ins and see if the problem ceases.

Just to make sure, you're not using any cable extenders to lengthen your ACD's cables to the MBA right? Disconnect all other USB devices connected to your ACD's USB hub. Ensure nothing is blocking the ACD and the room is not hot and it's not in a confined space in a desk with no room to breathe.

Could you try all of that and report back? I know it's a lot, but test each idea individually then as a collective with all ideas checked.

I am going with one of the following issues as being the root cause. One, cable or connection is bad. This could be a bad cable, twisted cable, bad port, badly connected cable either at port or into ACD, or cable has been bent or otherwise damaged internally (check each cable connecting to each port for proper fit). Two, the power isn't flowing properly to the ACD or ACD is overheating internally. This could be from too many devices connected to the power surge protector or UPS or too many running from ACD's power. It could also be a bad UPS (or bad UPS software), or simply an outlet that isn't grounded, or some other power related issue. Three, the MBA is overheated, or the GPU isn't cooling properly, or the CPU isn't cooling properly, or the vents are blocked, or there isn't ample cooling space, or the area isn't very cool or some variation of any or all of those possibilities.

I would like to see the results with the ACD plugged into an outlet that isn't driving anything else and only has a high-quality surge protector in between it. I would also like to see the results if the ACD's power to the MBA is not being used, and the ACD only has the USB and Mini Display Port cables connected to MBA without cable being stretched, twisted, or otherwise not in perfect alignment with the power cable going off the other direction. I would also like to ensure the energy settings aren't causing the issue. I would also like to ensure that the MBA doesn't have a bunch of plug-ins running in a browser when the flickers happen.

That is the testing I would try to see what happens when testing each and every one of these possible problem theories. This could be something really simple.

I very rarely will get a flicker, but it always seems to be when something weird happens AND I am running a plug-in in a browser. For instance, if I select for a video to go to full screen within Safari it might flicker for a brief second right before going to full screen. Sometimes when MBA is running and I connect it to ACD it will flicker for first second until I get cable absolutely perfectly connected. And I have noticed a flicker when moving the MBA and the display port cable seems to be moved or bumped or twisted in some way.

habbakuk
Mar 18, 2010, 11:19 PM
Ahh, Scottsdale. I will admit to hoping that you showed up for this thread, and you certainly didn't disappoint. I'm also glad that I'm plugged in to the 24" display right now, so I can see most of your incredibly thorough set of suggestions. Many thanks for that, and I'll try to hit as many of the points as I can; I'll abbreviate your suggestions because they are posted just above. I've tested each one individually, to no avail. I'll just reiterate that I'm on my second display right now, thanks to some kind souls at AppleCare, and while most of the tests I've done are on my MBA Rev B, I can replicate the flickers with my wife's MBA Rev B.

<Scottsdale>What apps are running when this happens?

Generally, I'll have multiple apps running. The number of apps running seems to make no difference to the frequency of flickers. For example, at the moment, the screen is going black for a second every couple minutes or so, with a rare flicker, and I'm only running Safari. The only plugin I run is Glimmer Blocker.

<Scottsdale> Energy Saver settings.

Unchecked the recommended box; no difference. Tried the suggested sleep settings; no difference.

<Scottsdale> Heat and electricity.

I've now been home and plugged in for five minutes, and am experience the flickers and black screens almost immediately. Yesterday I had about 1/2hr of good monitor time before the flickers appeared. After 40 minutes or so, I'm getting the horizontal lines, but haven't had a black screen for 40 minutes. I used to tuck the MBA on the stand of the ACD, a slight bit elevated, so I'd have more desk space. I've also tried letting it sit on the desk (wood), between keyboard and monitor. No difference. I brought the UPS home from work yesterday to test. Before, the ACD it was plugged in to its own outlet directly. There are no other devices in the apartment on the same circuit at the moment. CPU temp ranges from 55-70, fans come on as load gets heavy, stay off when not.

<Scottsdale> Twisty cables?

Cables are cleanly run to each port, no twists. (Gently) tugging and twisting on each cable at any stress point does not induce the flickers.

<Scottsdale> Run power from the adapter, plug into the monitor

I was most curious and hopeful about this suggestion - sadly, the problems are still present when running power from the adapter, and MD and USB to the ACD. Switching back to the ACD-based power still has the problem.

<Scottsdale> Web browser.

Often, I'm just running MATLAB and coding, with nothing else running. Same flickers.

<Scottsdale> General cable management

No extenders, problem happens with/without the iPod Nano plugged in Plenty of room around the ACD. Most of the headaches happened during this winter, and it was pretty cold in the room.

<Scottsdale> Specific hypotheses:
I doubt the cable/connection is bad - physical stress doesn't replicate the problem. Power is unlikely to be the issue - the ACD is getting a clean 60Hz 120VAC for sure - there is no load on the UPS, and with the UPS out of the circuit, the problems persist. The outlet is properly grounded. Heat is not likely to be an issue; the problems occur with the CPU at low temps (50C, enclosure at 27-31C, PS at 51-44C, and wireless at 34C).

Thanks again for sharing your experiences, and all of the tips. Maybe some of the feedback will prompt some follow-ups, but if not, I'm really grateful for the suggestions. At least when I call AppleCare again, I can honestly claim I did everything I could think of, and then some.

stoconnell
Mar 18, 2010, 11:53 PM
I have a 24" Dell (1920x1200) at work that I just tried to drive today with the MDP-> DVI adapter; it works beautifully, with no sync issues.
I've tried to play a bit with the settings stoconnell mentioned; it doesn't seem to matter whether the display is set to sleep or whether it is set to remain on forever. The computer stays quite cool to the touch, unless I'm running something processor intensive, and the vents are not blocked. I've tried elevating the computer a bit above the desktop, as well, but there's no indication that it is overheating.

Are you using the same keyboard/mouse combinations at work and at home? Do you use USB at work and Bluetooth at home? I was wondering about the MBA power source, but you already addressed that in your last post.

I do find it very interesting that it is able to drive a different brand of monitor at the same resolution (albeit a slightly different connection direct MDP vs. MDP -> DVI) under similar load conditions, etc.

Do you see a difference if you don't clam shell the MBA while connected to the monitor? I don't recommend it long term (just as an experiment -- I cannot work like that, drives me (more) batty).

agaskew
Mar 19, 2010, 03:01 AM
I don't know how practical this is for you to do, but how about taking your MBA in to your Apple store and asking if you can hook it up to one of their ACDs?
That might help to figure out if the problem is with your MBA or the ACD. Seems unlikely to be your MBA though from what you've already said.

One other thing is to check for environmental issues that might be affecting your ACD. I once had to help someone with a display that would flicker badly but intermittently. After a lot of fruitless looking, I realised the flickering only happened when someone used the microwave in the room next door. You could try moving the ACD to a different room for example.

Another possibility is that you have been unlucky and had two faulty ACDs - it happens.

habbakuk
Mar 19, 2010, 06:47 AM
Am using a bluetooth keyboard/mouse combo at home, and I run it without any peripherals at work. Same problems happen running in clamshell or open, and driving the Dell at work was done with the MBA open. Running it open is difficult for me as well.

It is certainly possible that I'm 0/2. I don't think that the problem is environmental, or interference based, because the flickers can happen at any time of day or night that I've tried using the monitor.

Mactagonist
Mar 19, 2010, 12:22 PM
Am using a bluetooth keyboard/mouse combo at home, and I run it without any peripherals at work. Same problems happen running in clamshell or open, and driving the Dell at work was done with the MBA open. Running it open is difficult for me as well.

It is certainly possible that I'm 0/2. I don't think that the problem is environmental, or interference based, because the flickers can happen at any time of day or night that I've tried using the monitor.

You might try making your home setup as similar to the work one as possible (IE Dont use BT accessories) and see if they is any difference. Since you have a known working configuration it is just a process of elimination to find the issues. Or you could just get frustrated and sell the ACD and buy a Dell for home with an extra power adapter and a USB hub! :)

Scottsdale
Mar 19, 2010, 03:13 PM
habbakuk. Sorry none of my thoughts worked. I am stumped unless it's either the ACD, cables on the ACD, or somehow the BT or wireless devices causing interference?

You might try making your home setup as similar to the work one as possible (IE Dont use BT accessories) and see if they is any difference. Since you have a known working configuration it is just a process of elimination to find the issues. Or you could just get frustrated and sell the ACD and buy a Dell for home with an extra power adapter and a USB hub! :)

I would definitely not drop the ACD for a Dell. Surely there is a solution here. My ACD is the most beautiful display I have ever seen. In addition, it's truly the ultimate docking "station" for the MBA. I am looking forward to a potential 27" and possibly even 32" LED ACDs to be released soon with an updated MBA.

I just wish there was a simple fix to this, but I wonder if it could be something else like frequency interference with another device??? Especially when thinking of BlueTooth being used. Has the OP not used the BlueTooth devices and tried it to see if flickering still occurs? What if it were something with frequency like being plugged into the same circuit as a large LCD TV? Consider what a microwave does to some things. Sometimes a microwave makes lights flicker or puts wavy lines on a TV. I guess I would think about those possibilities as well as other devices being on the desk that use power. I know that power can interfere with devices, and I assume this is a power source or frequency related problem IF it's not the ACD itself or the cables going from ACD to MBA or from ACD's power to power source.

Sorry habbakuk. I hope someone can figure this out for you.

stoconnell
Mar 19, 2010, 03:27 PM
Am using a bluetooth keyboard/mouse combo at home, and I run it without any peripherals at work. Same problems happen running in clamshell or open, and driving the Dell at work was done with the MBA open. Running it open is difficult for me as well.

It is certainly possible that I'm 0/2. I don't think that the problem is environmental, or interference based, because the flickers can happen at any time of day or night that I've tried using the monitor.

The thing I was driving at was taking BT out of the equation and seeing if that helps at all. Also, what about running in clamshell mode at work? Either with a USB keyboard and mouse or BT peripherals (USB vs. BT).

The only other thing that came to mind would be to see what refresh frequencies are being chosen: the Dell I am using (2407WFPHC) is 1920x1200@60Hz. Maybe the Apple is going at 75Hz and is driving things harder.

Mactagonist
Mar 20, 2010, 09:58 AM
habbakuk. Sorry none of my thoughts worked. I am stumped unless it's either the ACD, cables on the ACD, or somehow the BT or wireless devices causing interference?



I would definitely not drop the ACD for a Dell. Surely there is a solution here. My ACD is the most beautiful display I have ever seen. In addition, it's truly the ultimate docking "station" for the MBA. I am looking forward to a potential 27" and possibly even 32" LED ACDs to be released soon with an updated MBA.

I just wish there was a simple fix to this, but I wonder if it could be something else like frequency interference with another device??? Especially when thinking of BlueTooth being used. Has the OP not used the BlueTooth devices and tried it to see if flickering still occurs? What if it were something with frequency like being plugged into the same circuit as a large LCD TV? Consider what a microwave does to some things. Sometimes a microwave makes lights flicker or puts wavy lines on a TV. I guess I would think about those possibilities as well as other devices being on the desk that use power. I know that power can interfere with devices, and I assume this is a power source or frequency related problem IF it's not the ACD itself or the cables going from ACD to MBA or from ACD's power to power source.

Sorry habbakuk. I hope someone can figure this out for you.

I agree the ACD is a nice, all in one solution and a gorgeous monitor, but there is a limit to how much time and effort I would spend trying to fix something that should exist only to make my life more convenient! :) Especially when there are other off the shelf solutions that are known to work perfectly!

Scottsdale
Mar 20, 2010, 03:38 PM
I agree the ACD is a nice, all in one solution and a gorgeous monitor, but there is a limit to how much time and effort I would spend trying to fix something that should exist only to make my life more convenient! :) Especially when there are other off the shelf solutions that are known to work perfectly!

That's just it, many of us have 24" LED ACDs that work perfectly.

RLUK
Mar 20, 2010, 06:41 PM
.

RLUK
Mar 20, 2010, 06:42 PM
The issue with the Cinema Displays seems to affect other models of Macs too. My ACD flashes to a black screen intermittently with no apparent pattern and has been doing it since I bought the screen 3 months ago. It is connected to a 13" MacBook Pro

There is a discussion on the Apple support pages that has been going on for over a year and yet Apple are still no closer to finding a fix :(. http://discussions.apple.com/thread.jspa?threadID=1902288&start=135&tstart=0

Some of the symptoms seem similar to the problems experienced with the iMacs screens recently. I'm hoping for a firmware update to resolve this as the display is perfect otherwise.

habbakuk
Mar 22, 2010, 08:09 AM
Hi all,
Spent some time this weekend reinstalling OS X. Unfortunately, the screen flashed black during the hard-drive wipe (booted off the Snow Leopard install CD) and continued sporadic glitches while using a brand new user account on a brand new install, with no peripherals except the monitor attached.

I think I'm about done here; I've now spent a good few hours attempting to troubleshoot something that should simply have worked out of the box. Am not sure what I'll do now, but thanks so much for all of your suggestions!

Just to close out some suggestions; going to the Apple store and "trying" their monitors isn't really going to help - I found the first time that the problem could be as infrequent as once ever couple hours, which was still enough to make me feel like a sap for paying for something that didn't work, but way too long to stand at the store trying to get some work done.

I'm also disinclined to suspect any sort of RF interference. LEDs are driven by a different mechanism than TVs which ought not be susceptible to the same sort of interference. The "display flashed black" problem points to a different source as well.

It sure is a pretty monitor, and I do love the "docking" aspect, but as of now, I'm sad to say, it is more trouble than it is worth.