<p>Hi<br> I have a Mamiya 645 with a Phase One Back ( P30, by the way) and yesterday an error start to blink on the LCD : " no Fb" Reading the manual make me a little more confused about this since it says that this problema occurs whan the back is not properly installed, or when the dark slide is inserted in the magazine...<br> Has any of you experieced such a problem? Can anyone give me a hand?<br> Thank you very much <br> Fernando Brito</p>