I am using thunderbolt to connect to an imac 27" as a second screen - but the screen keeps going to black for a few seconds then returns - any known fix for this? It's incredibly annoying.
Connecting from iMac (27-inch, late 2013) Mac OS X (10.9.2) - to iMac ( 27-inch, mid 2011) Mac OS X (10.7.5)
iMac (27-inch, Late 2013)
Hi gun4hire!
Here is an article that will help you with troubleshooting this issue with your external monitor:
Apple computers: Troubleshooting issues with video on internal or external displays
http://support.apple.com/kb/ht1573
No video or no signal, image distortion, "snow," or flickering
Check connections
When using an external display be sure to check the following:
- If you're using an Apple notebook, confirm the AC power cable or adapter is securely connected to the computer and the cable providing power to the display is also secure. It is always good to have your notebook connected to AC power when an external display is in use.
- Confirm display adapters are fully seated in their respective connections and that they are supported models and for the computer and display. Refer to these articles to assist you with adapter compatibility and further configuration information:
- Remove all display cable extenders, KVM switches, or other like devices and retest to determine if the issue is resolved.
- Try unplugging the video adapter or cable and then plug it back in.
- If more than one video adapter is in use (or "daisy-chained"), troubleshoot by using only one adapter.
Example: A mini DisplayPort to DVI adapter connected to a DVI to HDMI adapter is an unsupported configuration because there is a series of adapters in use.
- If available, try using a different display and or adapter (or use a different connector by using DVI instead of VGA, for instance).
Reset the system
You can reset the Mac's parameter RAM and SMC.
Reset the resolution
Start by resetting the Mac's parameter RAM. If the display does not come up, was previously set to an unsupported resolution, and still results in no video:
- Start up in Safe Mode.
- From the Apple () menu, choose System Preferences.
- Choose Displays from the View menu to open the preferences pane.
- Select any resolution and refresh rate that your display supports.
- Restart your computer.
Thanks for coming to the Apple Support Communities!
Cheers,
Braden
targeted iMac(27-inch) - screen flickers black - any fixes?
