2 Replies Latest reply: May 9, 2012 5:35 AM by OwenNRL
OwenNRL Level 1 Level 1 (0 points)

I have been using my iMac for more than a year with a mini Displayport adapter to DVI and external monitor.

This morning it seemed fine until the external display started flashing and then slowly faded to grey/white completely and then black.


I went and purchased a brand new Samsung SyncMaster SA450 and connected it.


The display comes up and then goes off.  When "on" the picture is grainy and distorted.  Monitor will not stay sync'd.


Is it the mini DisplayPort adapter or the displayport itself?

iMac (24-inch Early 2008), Mac OS X (10.7.3)
  • 1. Re: external display
    X423424X Level 6 Level 6 (14,190 points)

    If two monitors from the same connection appeared to fail I would then think it is the video card itself.


    You can see if smc and pram reset has any effect but I doublt it will.  You may have to take this to apple for repair if that is possible.


    With respect to mini-displayports, I'll mention the following, but I am not sure this applies to you since you were getting signals to the monitors.  Make sure the mini-displayport plug is pushed firmly in so that essentially all the metal part disappears inside the socket.  Mini-displayport plugs can be a little tricky in that you need to make sure the plug is fully seated in their socket.


    You could try another cable or adapter as a cheap experiment but I also doubt this is the problem here too.

  • 2. Re: external display
    OwenNRL Level 1 Level 1 (0 points)

    Actually, as it turns out it was the Mini DVI to DVI adapter that failed.