I just switched cable service providers and the new HD feeds only show up in letterbox format on my Sony 53HS20 4:3 tv. Previously I could zoom in on the picture to fill the entire screen, but the new STB doesn't seems to allow this. Is there any hardware that I could insert between the STB and TV that could modify the viewing area? Routing the picture thru a blu-ray player? I'd prefer to not replace the tv as long as it's still serviceable.