Thanks for posting your question in the Sling Media Community. To answer your RMA-related question first, if the Slingbox does need to be replaced, you would want to contact our customer support department directly at 1-877-GO-SLING. The technical support representative might have you go over a few additional troubleshooting steps, and if necessary, they would look into replacing the unit.
Before doing that, though, there are a few other troubleshooting steps I would suggest. It is not uncommon for users who are experiencing video issues to be impacted by SOC (Selectable Output Control). What that basically means is that with a lot of current set-top box models, if you are simultaneously using an HDMI cable from your STB to your TV, and using another connection type from your STB to your Slingbox, your STB will automatically shut down one of the video feeds. This not a feature of the Slingbox, but rather the cable box itself. If you have an HDMI cable running from your cable box to your TV, I would suggest removing it, and then continue with the M1 setup process. If you get video after doing that, you should be all set going forward. To get video feed directly to your TV, you can utilize the pass-through option with the Slingbox. Using component cables, you can run an additional connection from your Slingbox to your TV via the output ports on the unit. That way you still get video to your TV, and your Slingbox works without issue.
If you don't have an HDMI connected, or if the problem persists after that, I would recommend doing a hard reset on the unit. Hold the reset button on the back panel of the Slingbox for 30 seconds, and that should restore the unit to its factory settings. Then attempt the configuration process again. Beyond that, if the issue continues, feel free to give us a call and we'll get you taken care of.
Sling Media Support Team