First make sure your bolt is all the way back and fresh battery. Then turn on your marker, if when you put your finger in the breech the light changes to a solid light, your eyes are working.
Like the Tadao boards, they read when the bolt passes the eye and on the return stroke, so with out air, it is going to read a block/malfunction because you cannot move your finger that fast.
Like the Tadao boards, they read when the bolt passes the eye and on the return stroke, so with out air, it is going to read a block/malfunction because you cannot move your finger that fast.