Hello there, rogerpan.
The following Knowledge Base article provides some in-depth instruction on troubleshooting Cinema Display:
Although the entire article provides very useful information, you may want to review the following section in detail:
No video or no signal, image distortion, "snow," or flickering
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 resolutionStart 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 reaching Apple Support Communities.
Thank you for your response.
My 23" Cinema HD Display had been working on my 2011 15" MBP since June, 2011, then stopped working March, 2013.
I did tried everything on my 23" Cinema HD Display to connect my 2011 MBP 15" through Thunderbolt to DVI, and it never turn on.
So right now my 23" Cinema HD Display only work on my old 17" MBP through DVI adapter.
I ordered a new 24" LED monitor, will receive on 6/13 to replace 23" Cinema HD Dispaly.
I think one of component below having issues.
1. 2011 15" MBP Thunderbolt port.
2. Apple Thunderbolt to DVI adapter.
3. 23" Cinema HD Display.
I will try to isolate it and try more test.