From some other similar posts out there I gather that os x mountain lion is not compatible with the hdmi output ? Therefore I attempted to downgrade from mountain lion to OS X Lion but unfortunately apple would not allow me to retrieve this software because the new version over rules all previous versions. Any other suggestions ? There must be another way of establishing a connection between a mac and a tv ?
I have the same problem. The only difference is that I am trying to connect to an external display using Mini DisplayPort to VGA adapter. I have tried with two different displays - a TV, Samsung C8000 TV; and TV-Monitor, Samsung SyncMaster P2470HD, both of them with no success. When I connect the adapter the screen turns blue for a second, the TV, just like yours, says 'No signal' and the Mac itself does not find any external displays. I have tried a variety of solutions - resetting PRAM, SMC, but nothing helped.
The AirPlay is not an option for me, because I want to use the Mac with projectors (HDMI adapters are not a solution, because most of the projectors I use are old and have VGA ports only).
I will try connecting it to a projector tomorrow. Let's hope it runs smoothly.
After reading in a dozen of similar forums I've come to realize that this particular issue is a common problem amongst MB users..Worldwide !
To be quite frank I am very disappointed to say the least ! This is absolutely mind boggling given the fact that it's a function you would normally take for granted with other laptop brands, yet here we have Apple the dominating computer brand in the world and it cant even connect to a tv ! This may sound like a drastic solution but I think I will buy another cheap laptob just so I can connect to my Tv !
! ! ! ATTENTION - SOLUTION - FOUND ! ! !
Today I went to see a Genius who was very friendly & helpful and explained to him the whole dilemma with my Tv & MB not acknowledging eachother via an HDMI cable yada yada yada...So he went ahead and tried just about every thinkable thing incl. trying to connect with an VGA cable which to my utter surprise actually worked ! Nevertheless the HDMI cable never connected no matter what he did. I asked him whether the cause for the problem was a software issue and his response was that most likely it was a hardware issue. At this point we both became frustrated, he then proceeded to the backroom and came back out with an Mini DisplayPort to HDTV Cable by BELIKN..AND LO AND BEHOLD: IT WORKED ! ! !
Cheers Everyone !