Any help here?
If you have an iMac with Thunderbolt, any other Mac with Thunderbolt can use it as a display. The iMac will play both the video and audio from the other Mac.
- Connect the Thunderbolt cable to the Thunderbolt ports on each computer.
- Make sure both Mac computers are turned on and awake.
- Press Command (⌘)-F2 on the keyboard of the external display Mac.
- If you want the external display Mac to play audio as well as video from the primary Mac, choose Apple menu > System Preferences, click Sound, and then click Output. Select the external display Mac from the list of devices.
If you have a 27-inch iMac with a Mini DisplayPort, any other Mac with a Mini DisplayPort or Thunderbolt port can use it as a display. Make sure you have a Mini DisplayPort to Mini DisplayPort cable.If the primary Mac has a Thunderbolt port, it can play its audio on the iMac as well as its video. If the primary Mac has a Mini DisplayPort, the iMac may be able to play its audio. To see if it can, go to the primary Mac, choose Apple menu > About This Mac, click More Info, and then select Audio (Built In) below Hardware in the Contents list. A list of your computer’s audio devices appears. If HDMI Output or HDMI/DisplayPort output is listed, your computer’s Mini DisplayPort can send audio. Make sure you use a Mini DisplayPort cable that carries both audio and video.
- Connect the Mini DisplayPort cable to the ports on each computer.
- Make sure both computers are turned on and awake.
- Press Command (⌘)-F2 on the keyboard of the external display computer.
- If you want the external display Mac to play audio as well as video from the primary Mac, choose Apple menu > System Preferences, click Sound, and then click Output. Select the external display Mac from the list of devices
To turn Target Display Mode on or off, press Command (⌘)-F2 on the keyboard of the external display Mac.
When Target Display Mode is on, the external display Mac displays the primary Mac’s open applications. When Target Display Mode is off, it displays its own open applications.
http://support.apple.com/kb/PH4469