HR20 only displays HD channels now

[btrain]

Help - My HR20 will now only display HD channels. When I switch the channel to SD I lose the picture and all that comes thru is audio. From there, I power cycle the HR20 and the picture comes up off-set to the left. When I change the channel an HD channel it realigns and comes up fine.

I'm using a Sharp LCD connected via HDMI. Any help would be appreciated...

Thanks.