Audio-vis out of sync.

I've read older posts and I don't think they apply to my problem.The audio is out of sync ONLY on the network channels. It was one or two at first but is pretty much all of them now(not PBS) All the others are fine. Recordings from these channels are garbled,too.

I have a simple set-up with an older TV(not smart),no sound system and an older(non-Genie)box - yes the box might be going but wouldn't it affect all channels,then? Could it be a dish problem?

Hope someone can help!