Originally posted by tcom - when to subject was more distant than the actual focusing distance, it went a bit towards minimal focusing distance, stopped briefly moved again a bit in the same direction, stopped briefly until it reaches the minimal focusing distance.There it stands still, AF indicator blinking.
Good description! It is revealing.
Because, as a matter of fact, one of the few advantages of phase AF vs. contrast AF is that the direction of correction can be derived from a single focus sensor measurement.
I.e., your lens moves in the wrong direction. It does so twice, then your firmware gives up with the blinking signal.
An easy way to achieve this is to revert-mount a focus sensor or its plug (if possible at all).
I propose to manually select any of the 9 cross sensors and study if they all show the same error.