MacBook Pro or Air no display on TV

Trying to connect MacBook Pro and/or Air to LG TV via VGA and adapter. Both Mac's don't show TV as display. Do I need to make any set up? Thank you.

Please read through our Sticky thread regarding connecting your Mac to an external monitor or TV. Go to this LINK.

Chscag, Thank you for information. Tried all what says, but still have no result. Additional info may help do see what I use, 1) MacBook Pro 7.1, Mac OS X, Ver 10.6.8, Intel Core 2 Duo; 2) MacBook Air 11 Mid 2011, Mac OS X Lion 10.7.5, Intel Core i5; 3) Rocketfish VGA adapter. When I connected LG TV to ether MacBooks my TV shows new device added and I make changes to RGB. But TV shows no signal. I disconnected VGA cable from TV and computers, but got nothing. Usually, I use PC laptop with TV via VGA without any issues, but with MacBooks nothing. With PC you should click Fn F8 to share screens, but Mac should be OK without. May be I am wrong? Sorry for long explanation.
Thx.

Thanks for the feedback. Hang on for a bit and hopefully Staff member bobtomay will see this post and offer some additional advice. He knows more about this subject than most as he's the one who wrote the Sticky post I directed you to.

Based on your response, am guessing you know how to make sure the TV has been changed to the correct input and that you are seeing "no" response on either Mac when you connect them.

And you are plugging your Macs into power and not running off battery alone - correct?

I would say either the cable or the adapter you have is defective - probably the adapter - particularly if you bought it from Amazon and possibly other places. See this review. The adapter would be my guess even without several reviews such as that one - they are just prone to failure more so than cables seem to be.

Does your LG have HDMI? If so, I would suggest you discontinue using VGA completely and move to HDMI. Grab a mini displayport to HDMI cable so that you can pass video and audio in a single cable.

(And I have no idea what it is you mean by "I make changes to RGB". You may want to explain that. I would still surmise the adapter is the culprit however.)

Bobtomay, thank you for help. My VGA cable is OK, because is working with PC laptop. I agree with your solution, VGA adapter should be bad. I thought, the new Cromecast will work with Mac's, but it slowly kills my WiFi if I am transmitting movie from the Internet. So, I need to buy HDMI cable and adapter or identify why Cromecast does't work.