3 Replies Latest reply: Dec 12, 2012 8:25 AM by Cosman
Cosman Level 1 (10 points)

Ever since I got a new MBP with the new thunderbolt port, any monitor I hook up to the port will turn on and off repeatedly for several minutes before becoming stable.  The monitor may turn off later, but usually stays stable after it has been connecteda while.


The monitor will drop out, showing the "no signal" text, then even going down to sleep mode (green light turns to yellow).


I took the MBP into the genuis bar and they diagnosed a bad mother board.  After it was replaced, the problem stayed the same, so it is not the mother board.


I thought it might be the thunderbolt adapter, but I have two of them and the problem occurs on three different monitors with either ofthe adapters.


The MBP screen is not affected.



MacBook Pro, Mac OS X (10.7.3), I7, 8GB, 750GB, Lion
  • BGreg Level 6 (17,495 points)

    You might want to post this in the MacBook Pro discussion here.

  • Knucklesmac Level 4 (2,225 points)

    I know this seems a daft question, but have you tried another Thunderbolt monitor? It could be the monitor at fault.

    Was the fresh rate setup correctly when you connected the monitor to your MBP?

  • Cosman Level 1 (10 points)

    I don't have a Thunderbolt monitor.  All 3 are chinese makes.  I do have two Thunderbolt to VGA adapters that I use among the monitors.  I didn't have this problem with the same monitors and my older MBP with a DVI port on it.


    I haven't touched the resolution settings.  Today, the monitor at work hasn't skipped a beat (I-INC 25 in).  Sometimes, it takes 5 minutes to decide to communicate properly.