I have a Blu Ray Samsung HTB-H4500R. This player worked for a few minutes before showing Protection message. Fan and inside cleared of all dust, but no improvement, even with lid off. Also no signs of components getting hot, or speaker wiring problems. Eventually fault cleared by removing front control panel, disconnecting the one ribbon cable and brush cleaning the reverse side of board with alcohol (where there were deposits of a sticky nature which were there from manufacture). Dust was attracted to these deposits causing a malfunction of possibly high impedance circuitry. The clue was that I had read elsewhere about disconnecting this panel on other Samsung Blu Ray players which cleared the fault and using the remote control for operation. I think the sticky stuff was used on screws going into plastic, and may have migrated with time.
John Pearce