Welcome to the forum.
Some of these issues were addressed in a firmware update patch. If you have a thumbdrive, you can update your firmware and that should fix the issue.
You can download that patch here:
My setup included a PS3 and a Samsung plasma tv bought 5 days ago. 1st attempt was a Rocket fish HDMI cable from PS3 to TV and had a problem with the screen going out irratically. It would then pop up a blue box that stated "mode not supported". This was while plugged into the HDMI slot # 1. Slots 1,2,and 3 on the back of the tv all had same results except for the slot #4 and the side of the tv which worked fine.
Per a friends request I tried a Philips HDMI cable and had almost same results except this time no blue box just the screen going blank. It will go blank for about 4 seconds then come back on for about 5 seconds and repeat.
Per Best Buy the recommended the $80 Monster cable which I have hooked up not but had not had time to watch a movie or play a video game for a extended amount of time.
BB reps thinks possibly a TV failure. I cannot think of anything else that it could be. Multiple cables and still problems. Im wanting to try a friends PS3 and see if problem chenges.
Anyone have a suggestion of what this could be??
Thanks in advance