It could still be the cable, I have a HDMI cable from monoprice that experienced the same issue with my PS3 on my CRT RP. I changed it with the HDMI cable that came with the 360 elite and it works flawlessly. The cheap one works with the 360 on that set, and both cables are 1.3a. The PS3 works with the MP cable and the 37" LCD in the bedroom though. I think perhaps it is a problem with the CRT and the HDCP handshake, or maybe a timing issue crops up? Anyways, I'd try another 1.3a cable just for troubleshooting purposes.