Samsung TV changes channels on Comcast

[gopcs]

I need help. Bought a Samsung 19" TV for the kitchen, model LN19A450C1D. Within 30 minutes after going through Setup, the TV had changed channels by itself from HD 5.1 to 2.1. I called the retailer, HH Gregg, and then called Samsung. Neither had heard of such a problem. I returned the TV to HH Gregg and exchanged it for another TV of the same make/model.

Now the second TV is doing the same thing. In a span of about 5 hours, it has changed from HD channel 5.1 to 2.1 six times.

The HD service is Comcast. I am not using the STB. The cable TV service connects directly to the television set.

The remote is not being press accidentally. In fact, the batteries were removed from the remote, and the TV still changed channels by itself.

I placed the TV in another room, and attached rabbit ear antenna, then ran setup for over-the-air broadcast channels. It stayed on channel 5.1 HD all afternoon. When reconnected to Comcast and setup for cable channels, it changed from channel 5.1 to 2.1 in less than 30 minutes.

Any chance there is a signal from Comcast that may be causing this? I called Comcast, and they deny any responsibility. Any other ideas before I exchange this one for a different brand?

Thanks.

[gopcs]

I think the mystery is solved. Seems Comcast does not send local channels in HD on regular cable service. The TV salesman said they did, as did the first CSR I spoke with at Comcast.

After having the same problem of channel 5.1 changing to 2.1 on two different TV sets, I called Comcast back. I spoke with a CSR and a Supervisor. Both told me that to receive any HD programming, a decoder box is required.

Seems the HD programming I was receiving without the decoder box was ingress to the cable network from the broadcast television transmitters. After installing a decoder box, the Samsung HD TV is stable.