Pentax 6x7 (mlu)- blank frame

[Neil Grant]

...the camera has given an unexposed frame half way through a film. I don't think it was operator error. Other online sources suggest failing battery (maybe silver oxide better than lithium) or some mechanical problem within the camera. Anyone here encountered this??
thanks.

 

[Guillaume Zuili]

Usually when you get an unexposed frame the mirror get stuck and you cannot shoot further without resetting the camera with a needle on the little black button (on right side of camera if memory is good, I don't have the camera with me while I'm writing). Failing battery or this problem have two things in common, you cannot operate the camera further,
So I think it's an operator error.