"so the problem lies in the PS3"
Or the TV. Or the cable. You're making an assumption that you have not proven through investigation.
Again, your display is flaky in regards to both HDCP and 1080i over DVI. A different cable may fix the problem, though it's the least likely culprit. I would also bet that it is pretty likely that if you hooked up another PS3 of the same revision it would still give you issues. Just because HDMI out from a Bluray player works doesn't mean that HDMI from everything will work on that input. It means you got lucky that time.
So, since you've already reset the PS3 video output and tried 480i over HDMI without success, your next step is to get a new cable. If that fails, then borrow a friend's PS3 to see if that functions. Hook your PS3 up to a friend's PC monitor or HDTV to see if it will physically spit out anything over HDMI without failure.
The easy solution? Hook the PS3 up using component video to the CRT. I'd imagine 3rd party PS2/PS3 component video cables are under $5 off Amazon.