Question:
If one wore tefilin without the yud touching the bayis, has he fulfilled the mitzvah or must he re-wear them?
Answer:
He doesn’t have to put them on again, and it is obvious that he should try to fix it as soon as possible.
Sources:
See Pischei Teshuvos 27-6, that if one noticed that the yud wasn’t touching the bayis after he took the tefillin off, that he doesn’t have to put them on again. The reasoning is because there are opinions that if the yud is touching the base of the tefillin, even though it wasn’t touching the bayis it is alright, and there are also opinions that there may be a little air in between.
