Both times the machine would not turn on after the cable was restored. it was necessary to unplug it from the power source, plug it back in, then all OK.
Angeline
(OSX.4.10 Safari 2.04.4)
Once a few days ago, and again yesterday morning. The iMac shut down (black screen) simultaneously when TVs suddenly lost cable. (No electrical power outage.)
First I posted in my ISP's Macintosh forum. Apparently no one else has had the problem so far.
I phoned AppleCare, and spent some time with the tech. I had the modem plugged into the same surge proctor as the computer and my camera dock. She advised moving it to the surge protector for my printer. She then opined that the cable modem was sending a surge. I have had this modem for several years, perhaps as many as 7.
Today I called my ISP, and am scheduled to have a new modem delivered Monday morning. What bugs me is that the tech talked about what might have to be done.... changing cables inside and out, etc. that would cost almost $40/per hour., which tells me the guy Monday will do all he can to say I don't need a new modem.
So I'm wondering if the best way to duplicate the problem would be to unplug the modem from the power source, or disconnect the cable from it.
Thanks!
Angeline

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic