Mass Effect 3 Crashes/Freezes in London (Singleplayer - PS3)

Hi, I have a problem in Mass Effect 3 PS3 when I'm in London just after eliminating the Banshee and be rescued by Coats and Anderson, after the cinematics, the game just freezes and I have to force restart, and probe on another PS3 system, another disc of Mass Effect 3, erasing the Extended Cut and playing from the beginning of London, and I have no solution, anyone can help me with this?, I started from Mass Effect 1 and is frustrating not being able finish the story after 140 hours of play.