Imac 2nd display not working.

Jul 8, 2024
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Hi all,

I have a late 2015 imac, its been working faultlessly...until a couple of weeks ago, when the second display stopped working, I've tried other monitors, leads and both Thunderbolt ports, it did come back briefly, but failed again on the next reboot and hasn't worked since(about a week now) I just wondered if this is a common or known fault and if so, is it fixable?

May 7, 2023
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I have not heard of any issues with the iMacs and external displays.

Have you tried to zap the PRAM or reset the SMC?

To zap the PRAM
  • Shut down your iMac.
  • Turn on your iMac, then immediately press and hold these four keys together: Option, Command, P, R.
  • Release the keys after about 20 seconds, during which your Mac might appear to restart.
You might hear a startup sound more than once, or see the Apple logo more than once.
When your Mac finishes starting up, you might need to adjust any system settings that were reset.

To reset the SMC
  • Shut down your iMac.
  • Unplug the power cord.
  • Wait fifteen seconds.
  • Attach the power cord.
  • Wait five seconds, then press the power button to turn on the computer.

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