Problem with TV or Cable?



I just bought a Vizio 47" LCD flat screen TV at Costco. I have Comcast service but only have one cable box from them. I used an RF connection to connect the new TV to cable, without the cable box, just to try it out.

My understanding is that without a box, all I would have fewer channels and that is how it works on an old TV in another room.

Here's the issue: when I channel surf with the new TV connected without the cable box directly to the RJ6, i get both analog and digital channels (great). Unfortunately, after i watch for a little bit, the digital channels freeze and once they do the only way to see them again is by turning off the TV and turning it back on. Analog channels continue to work fine.

I called both Costco concierge services AND comcast. Neither knows the answer. Is the comcast service actually showing me the HD channels (they were all network channels, abc, cbs...) OR was this magically coming over the air? If over the air, Costco said it may be a weak signal that caused the freeze. If it's not over the air, it shouldn't be a weak signal.

Any ideas?


Chris Muriel

Distinguished Member
It sounds very much like you are in north America.
You will be more likely to get useful answers if you post in the equivalent forums over there - is Europe-based.
I might guess though that Comcast monitors your cable return channel (AKA upstream channel) and the system disables the digital stuff when it doesn't detect a corrrect Comcast network ID or doesn't get any response at all from your TV.
I wonder if your TV has a QAM tuner/demodulator built into it (e.g. built-in cablecard) - this would be necessary to view digital cable channels over CATV.


Chris Muriel, Manchester, UK

The latest video from AVForums

Sony Bravia XR A80J OLED TV Review
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom