I am trying to go into target display mode on my iMac. Its a 2012 iMac which does support TDM. However, I don't have a standard iMac keyboard because I bought a refurbished Mac which comes with a different keyboard & mouse. That being said, I can't use the Command + F2 key combination to go into TDM. How am I able to without doing that?
Have you tried all the steps recommended by Apple?
Use Target Display Mode
Follow these steps to start using your iMac as a display:
1 Make sure that your iMac is turned on, and the other Mac is logged in to a macOS user account. 2 Connect the Mini DisplayPort or Thunderbolt cable between the two computers. 3 Press Command-F2 on the keyboard of the iMac that you want to use as a display.
After you press Command-F2, your iMac displays the desktop from the connected Mac.
If Command-F2 doesn't work
If your iMac doesn't switch to Target Display Mode when you press Command-F2, check these things:
• Make sure that the iMac you're trying to use as a display supports Target Display Mode. • Target Display Mode works only when your primary Mac is logged in to a macOS user account. For example, if your first Mac is at the FileVault login screen, pressing Command-F2 on your iMac does not enable Target Display Mode. You must first log in to your Mac (using a regular display, if necessary) before you can use an iMac in Target Display Mode. • Make sure that you're pressing Command-F2 on the keyboard that's connected to the iMac you want to use as a display. • In Keyboard System Preferences, if the checkbox is enabled for "Use all F1, F2, etc. keys as standard function keys," the key combination changes to Command-Fn-F2. • Make sure that your Mini DisplayPort or Thunderbolt cable is connected to both computers. • If you're currently logged in on the iMac you want to use as a display, try logging out to return to the login window. Then press Command-F2 again. • Some older Apple keyboards and third-party keyboards might not allow Command-F2 to toggle display modes. If this happens, use the keyboard that came with your iMac to toggle Target Display Mode on and off. • If your iMac is currently started up in Windows, it won't enter Target Display Mode. Target Display Mode isn't supported in Boot Camp.