Hey there Mr and Mrs Bongo,
Try using the steps below to get your Mac and TV connected again:
Connect your Mac to your TV
1. Connect one end of the video cable (or an adapter, if necessary) to the computer’s Thunderbolt port
, HDMI port, or DVI port
, then connect the other end of the cable to the TV’s video input port.
2. If you need to adjust the resolution on your TV, choose Apple menu
> System Settings, then click Displays
in the sidebar. (You may need to scroll down.)
Click the pop-up menu next to Resolution on the right, then choose Default for Display to automatically use the best resolution, or choose Scaled to manually select a resolution.
3. If you want your HDTV to play audio as well as video from your Mac, choose Apple menu > System Settings, click Sound
in the sidebar (you may need to scroll down), then click Output on the right.
Select your HDTV in the list of devices. If you want to play audio on a different device (such as your computer’s speakers or an AV receiver that’s part of your sound system), select it instead.
Note: If your Mac has a Mini DisplayPort
, make sure you use a cable (and adapter, if necessary) that supports both audio and video.
Use your TV as a display with Mac - Apple Support
For additional help, continue here: If you can’t see your Mac desktop on an external display - Apple Support
Take care!