Thank you for utilizing our online answer forums. the answer to the question you have is unfortunately no. The reason for this is because the TV will only input video and audio it will not output video and audio. This is the reason you need a Cable box with the Slingbox 500. Below I have listed you a few links to assist in showing you, what you need to setup the Slingbox 500.
As promised here are those links:
Hope this helps
Sling Media Moderation Team.