BeoVision 7-40 can process a PS3 signal, we connect them all the time without problem. If you haven't already, it might be worth doing a software update on your PS3. If that doesn't solve it I believe you have a faulty DVE board and as your set is under warranty your dealer should be able to sort it quite easily. HDMI is not a simple video signal

Call your dealer again. they have the ability to print you or email you a remote layout sheet for any PUC codes.

Does it only happen when watching PS3? could be a problem with that. Why does everybody automatically blame the TV?