Thanks for contacting us here in the Forums. We do apologize that you are having issues with your video. We have included a article below that may help with the issue that you are having. Check it out!
Watch on Slingbox.com plays audio but no video
The Slingbox Moderation Team
Thank you for participating in the Slingbox Answers forum. I am sorry to hear that you are having this issue. When you change the set top box that is connected to the Slingbox then you will have to reconfigue the Slingbox. Do this by going to setup.slingbox.com and change the AV source.
Hope this helps,
Sling Moderation Team