2007 Imac with 10.5.8 Leopard with mini-DVI port to HDTV not working I'm trying to hook up my IMAC mini-DVI port to my Samsung HDTV.  I have a (mini-DVI port to HDMI) adaptor plugged into a 15' HDMI cable.  This plugs into the TV's (DVI/HDMI) port. 

I also have a 15' audio cable plugged into the MAC's headphone port then to the TV's (PC/DVI) audio port.  Nothing works, video or sound.  TV says no signals detected.  MAC doesn't know it's connected. Does anyone have the slightest idea as to what the problem is? Do I somehow have to activate the mini-DVI port?
Apparently older Macs don't support audio through HDMI. Audio needs to be transmitted separately through the jack connection on your Mac, just as if attaching speakers.

Then depending on your TV could be jack or RCA.