Currently Being ModeratedMay 9, 2013 6:57 AM (in response to pollyraph)
I looked up "iMac 8.1" on everymac.com and it indicates this model has a DVI output, not a miniDisplayPort output. Are you sure you are using the correct adapter?
Also, your TV has to be set to the same HDMI input that you connected to your iMac. If its set to a different input, the Mac will not "see" your TV. (eg, if your iMac is connected to the TV's HDMI-1 input, on the TV you must select the HDMI-1 input). Note, also, that some TVs only support computer connections on certain inputs. Check the manual for instructions on this. (On my Sony Bravia HDTV, the manual is explicit that computers need to be connected to HDMI-4, for reasons not explained.)
Currently Being ModeratedMay 9, 2013 9:45 AM (in response to pollyraph)
The other issue with your older 2008 iMac is even if you get the right adapter and you can get picture from your computer to the TV, DVI doesn't output sound.
You would need to use your iMac's headphone jack with a a special cable that has mini stereo plug at one end and splits the cable into a Y configuration with left and right RCA jacks to plug in the back of the TV for the iMac's stereo signal.
Currently Being ModeratedMay 9, 2013 11:04 AM (in response to pollyraph)
What is your reason for hooking up your iMac to your TV?
There is another solution if you own a new or newer iPad (iPad 2 or greater).
If involves having a wireless router and your iMac, Apple iPad HDMI adapter and an iOS app called Splashtop Remote.
Currently Being ModeratedMay 9, 2013 7:00 PM (in response to pollyraph)
Im using it for screen sharng so can watch the movies on my mac on my tv, I have seperate cabes for the soud if needed but still cannot get the TV and IMac to find each other, all help references I need to select mirrror appearance in the display/colour in system preferences but that option is not available to me.
Currently Being ModeratedMay 9, 2013 8:09 PM (in response to pollyraph)
You need a mini DVI to HDMI cable for your video.
You are using the wrong cable.
You need one of these.
Message was edited by: MichelPM
Currently Being ModeratedMay 9, 2013 8:37 PM (in response to MichelPM)
Thank you so much i hope they sell them where i go , if not ill have to order online , Cheers