Thank you, for participating in the community forum. I see you're having some trouble with hooking up your Slingbox 350. You will need a HDMI splitter to convert hdmi into component. Have a look at the link below, it will help you verify that everything is hooked up properly.
Sling Media Support
I have Slingbox 350 and a TV with HDMI cable and set-up Slingbox with component video cables (worked fine), however Xfinity changed my box. My problem -new set top box does not have comp video ports only SD. Instructions do not cover a connection where HD video source and SD are the options on the set top box. Does anyone know how to set this up?