I assume you have already done a proper Forum Search for your model number in case other people have already answered your question ?
If so and that didn't help then check out this thread: https://community.sling.com/thread/3300?tstart=0
Come back if it that doesn't help either.
Thanks for prodding me. For some reason ( I think from a forum thread I had read), I thought the box was manufactured by Pace. (Comcast doesn't make it easy to find).
Per your recommendation re the relationship between Comcast and Motorola, I checked Motorola and found the correct model.
I can make the new setup work but cannot input a channel directly on my phone Slingplayer app as the new Comcast setup brings up another screen for me to Select, which I can't because the control screen is gone.
Probably doesn't make sense to you but at least I've got the Slingplayer working again.