S2440L, unsupported apple hardware, flickering?

Nevermind! It just started doing it again.

I'm using the cord that came with the replacement. I may try using the HDMI port and see if this helps.

Groshelle,

When the replacement S2440L arrived, did it come with its own power cord and AC adapter? Or are you still using the 1st monitors power cord and AC adapter?

Correct. I bought the original unit from Bestbuy. I returned all parts associated with the monitor to the store  and exchanged this for an all new package; cord and all. 

What I'm trying now is to move my computer further away from the display. I'm running a Macbook Pro "13 in clamshell mode in conjunction with the monitor. I would question the graphics card in the laptop but this operated fine for the first couple of months and the inbuilt display is perfectly fine. 

I'm hoping that this is a case of interference. Maybe the laptop being so close is causing this. We'll see....

If this keeps occurring I'm going to try plugging the monitor into a UPS to see if it's an unsteady current sensitivity that's causing this. 

As I type this, the screen is flickering a bit. 

Is it maybe a capacitor?

I'm no expert!!!

If I had a guess.. it would be a cheap bit in the port chip. 

Once again, I'm no expert. 

You stated, "I'm using the cord that came with the replacement.". Does that mean you are not using ANY cabling that shipped with the 1st monitor on the 2nd monitor?

Since your monitor only has an attached Dell Order number and not a Service Tag number, contact Dell Customer Support. Provide to them the following data so they can setup a parts exchange =
Email Address:
Name:
Shipping Address:
Phone number:
Order number:
Reason: Replace the GXYHH AC Adapter and the 5120P Power cord to see if it corrects the issues

I'm using a 13" macbook pro. But what baffles me is that there will be long stretches when there is no flickering. It seems if it was the graphics card or software (which I highly doubt) the flickering would be continuous. 

Are there a lot of wires around your monitors? Are your computer's on the same circuit or close to one another?

I sat my computer farther away from the monitor and it seemed to stop for quite a while. Ultimately, though, I'm a bit flustered by the whole thing. I don't need a part replaced, it's the monitor. 

I also have this issue. My monitor is attached to my Mac Book Pro 17'' i7, via HDMI ( with a Thunderbolt to HDMI adapter ).

One thing to add to what you observed, and what others say they observed, is that sometimes when I see it flicker, I see garbled graphics for a split second. This leads me to believe it's not power related per se, but having to do with the embedded hardware.

As has been noted in this thread, the flickering is extremely intermittent. Some days it will be fine, other day it'll flicker several times in the same 10 minute period. Other days it'll completely turn off for 1-5 seconds. Just when I begin to panic it comes back on.

Good morning - i have a 2012 macbook air and am facing the same issues (black screen, flicking etc) with the S2440lL.  I searched a lot in forums and verified a lot of people with the same problem, but none of the forums posted a solution for that.  Have someone was able to fix it or should i buy a different monitor?!

Hi Chris, I have the same issue with my Dell S2440L too; in fact I bought 3 monitors (1 for home and 1 for each office I have); I have connected each of them via HDMI cable to my new Mac Book Pro 15" (Retina Display) and all 3 monitors at each site has the same issue; the retailer has upgraded the HDMI cables but the issue persists and has not changed anything; the retailer wants to take each of the monitors back and test them however they did this with one of them 2 weeks after i set it up at my home; after 2 days they  said there was nothing wrong with it and returned it with same issue?? 

I think there must be an issue with compatibility? Which I find extraordinary; by the way the other computer i use at home is a Mac Book Air and it shares the same issues as my Mac Book Pro?? I think the issue lies with Apple software?? 

Unfortunately, Dell does not test/validate this monitor model on Apple hardware, ports, and software. Because of this, Dell does not have many troubleshooting steps to offer. You should post on the Apple Discussions Forum and see what they say.

 Some apple users have mentioned that using a thunderbolt to HDMI adapter or thunderbolt to DP adapter has had some success.

apple thunderbolt out --> thunderbolt to HDMI adapter --> HDMI to HDMI cable --> Dell monitor HDMI in

apple thunderbolt out --> thunderbolt to DP adapter --> DP to mDP cable --> Dell monitor mDP in

apple thunderbolt out --> thunderbolt to DP adapter --> DP to DP cable --> Dell monitor DP in

apple HDMI out --> HDMI to HDMI cable --> Dell monitor HDMI in

Check the apple Discussions Forum and see what they say:
https://discussions.apple.com/index.jspa

The notes below are from apple users, not Dell.
* Force RGB mode in Mac OS X to fix the picture quality of an external monitor
http://www.ireckon.net/2013/03/force-rgb-mode-in-mac-os-x-to-fix-the-picture-quality-of-an-external-monitor

* apple OSX 9.2 does not support DP1.2 MST

* Problem: apple OS v10.9.2 with UP2414Q/UP3214Q, DP (Display Port) selected to DP1.2 enabled and resolution at 3840x2160 60Hz, results in monitor image appearing spread across both tiles with a mess of garbled colors. apple OS v10.9.2 does not support 10 bit color panel or displayID EDID.
* Discussion: Installing the latest version of apple OS v10.9.3 for the macbook pro/retina will resolve the color distortion issue. Operating the 4Kx2K displays with DP set to DP1.2 and resolution at 3840x2160 60Hz will result in normal image. But your computer must have the dedicated Nvidia GeForce GT 750M GPU installed. The integrated Intel Iris Pro GPU is not 4K compatible.

* To get higher resolution 2560x1600 from an apple mDP you must get the $99 mDP to DVI-D Dual Link adapter. The standard $19 mDP to DVI is Single Link and will not work.
http://store.apple.com/us/product/MB571Z/A/mini-displayport-to-dual-link-dvi-adapter

* LUT3D calibration in monitor is only available on Windows. 10-bit workflow is only avaliable under Windows for all 10bit monitors

* U2713H/HM on apple: Forcing RGB mode instead of YCbCr to fix the image noise when moving items/flickering/thin diagonal lines = http://embdev.net/topic/284710

* apple cables are proprietary and have issues with Dell monitors. Some apple users reported success using this setup =
apple thunderbolt out port --> Accell B112B-001B UltraAV converter --> Dell cable --> Dell monitor DP in
http://www.amazon.com/gp/product/B003TSDG06

* apple devices are not BC1.1 compliant
The Dell USB side port #3 supports 1.5A charging only when the device connected to it is BC1.1 compliant. Non-BC1.1 devices (apple) will only charge at 0.5A so your apple device may not charge at this low level

* There is a bug in snow leopard that disables LCD (sub-pixel) font smoothing on many third party LCD displays, including models from Dell, Samsung, LG, HP, EIZO, and Lenovo

* mac pro operating system 10.9.1 (late 2013) does support the UP3214Q in 60Hz mode, but only in 1920x1080 mode.

* apple mDP pinstriping = Select the Custom RGB profile and nudging the blue and green down 4-5 points. The screen takes on a pinkish tinge, but the pinstriping becomes a lot less noticeable.

* Let me chine in and say I also have this problem and not only with the U2311H but with an Apple Cinema 20" DVI display. I don't believe its the monitor. My theory is that it is Snow Leopard. Certain users say using a DP video card alleviates this issue. I did not have this problem with leopard 10.5.8 but I believe started happening with 10.6.4 combo update. It also does not happen when using a dvi to VGA adapter. Also let me explain another reason why I do not believe the monitor is at fault. Connected to a Windows 7 running PC it exhibits none of this behavior. So the problem is the software not the hardware. Make sense? I believe apple royally messed up the latest snow leopard not only with this issue but overall OPENGL performance on nvidia based cards. I need to perform more tests. But like you I am seeing vertical pinstripes on certain solid colors. So if you have the option try an earlier version pre 10.6.4 or leopard.
wojowork

* Visual distortion with Dell Monitor on apple
* Go to System Preferences / Displays
* Click Arrangement and select Mirror Displays
* Return to Display pane
* Select Detect Displays
* From the dialog on your Dell, select the resolution that works best on your monitor
* If you want the Dell as an extended desktop, leave Mirror Displays selected. If you prefer the Dell to be your primary monitor when docked, then de-select it and select the Dell as your primary monitor