IMac only works if I use external monitor
by Ocean525917 - 4/5/12 11:14 AM
My IMax Intel 24" A1225 Freezes up (except mouse it will mover but nothing else) after log in. When it first happened over a month ago I had the finder window open trying to get to Disk Utility. If I restart the same thing happens over and over, including the sames program opening and about 10 minutes after the computer locks up the screen goes white, sometimes black.
Took it to tech support, they said it was the video card. Next day said they installed video card but that was not the problem and that I needed a new monitor. I said the monitor displayed fine crystal clear color. He said it was the inverter board attached to the monitor. I said replace the inverter board he said they can't because it sells as one piece. Got the computer back, purchased and installed an inverter board, problem not fixed.
Removed Mac monitor and with Mac monitor out I plugged in an external monitor and the computer works great. Went to disk utility and fixed HD files, did a long extended hardware check and all was good. Shut off computer and installed Mac monitor and turned on...everything works great. Did hardware test again and all is good. Did dist utility again and all is good.
Here is where it gets weird. If I disconnect the external monitor the computer locks up about 10 minutes later and the screen goes white. If I reboot with the external monitor installed all in good in MAC world. If I reboot with just the Mac monitor installed I opens the exact same programs that were open when it crashed over a month ago and then freezes and ten minutes later screen goes white.
Don't want to have the external monitor plugged in to work. Any suggestions or test that will determine what is really causing the problem would be greatly appreciated.
Also my computer just started turning on, from OFF not in sleep mode, all by itself at 7:00 AM. That is a first and I did not set it to do that. Has done it twice in a row so far. Woooo spooky and it is not Friday yet!!! Wonder what will happen tomorrow....