Thanks!
The thing is -- the cable that **didn't** work with the TiVo, works fine with the Apple TV. Does that still match up with the explanation of it as being a bad cable?
I got a new TiVo Bolt, model # TCD849000VO. My TV, a Samsung PNC50C7000, has 4 HDMI inputs. I plugged the TiVo into HDMI 4 and it worked great. I then unplugged the TiVo and moved it to the shelf where it's going to normally be. I plugged it into HDMI 1 and got a picture that was mostly red...