Trouble changing channels

Gornza

I have Cablevision in NJ. When changing channels from nonHD channels to HD channels (or vice versa) the channel doesn’t come thru.

The screen turns white, I see the small grey box in upper right of screen showing the resolution , and the channel number changes on my converter box, but the screen it changes too is then black (nothing).

I have called my cable operator and they said that sometimes HD channels don’t come in all the time and you have to wait or go to another channel first. But I am also having the issue going from a NONHD chanel to a NONHD channel. It seems that turning the TV off for a few seconds and then on again works.

1 more thing, I am using an HDMI cable connecting the tv to the Scientific Atlanta 4550HD box. SOmeone in another post suggested I switch from Native Resolution to 1080? Is that done in settings of my 4250HD ? Any ideas?