Wearing Tefillin on Chol haMoed / Minhag Frankfurt

A few pesokim accumulated from different Rabbonim - Rav Shlomo Zalman Ulman from Rav Wosner's Beis Din, Rav Nosson Gestetner, and Rav Yochanan Sofer of Erlau. After these pesokim the Shul in Bnei Brak started donning Tefillin on Chol Hamoed.

Michael FRBSH

The Baer Siddur (19th century) is the first source we find for taking the Tefillin off after KHT on the day of Kadesh Li. But actually we don't find the Minhag of taking the Tefillin off before Hallel in Ashkenaz until the 19th century, (as will be explained).

The concept of taking Tefillin off on Chol Hamoed before Hallel is found in the Taz and Mogen Avrohom, but this wasn't accepted in Ashkenaz in their days. The Chavas Yoir (about 100 years after the Taz, at the beginning of 18th century) was upset that people started taking Tefillin off, and he said they should be left on until after Musaf.
But in the 19th century the Minhag became common to take the Tefillin off before Hallel, and we find then the Oruch Laner quoting the Mogen Avrohom and Taz saying that should be done, but he also brings a diyuk from the Maharil that he left the Tefillin on later.

In SMA #5 there will be a chapter about this issue IYH.

Michael FRBSH

The Gr'o held one should not put on Tefillin on CHol Hamo'ed even in Chutz Lo'oretz, on days which are not Yom Tov for anyone, because Chol Hamo'ed itself is considered like a Yom Tov.
Since the Ashkenazi Yishuv in Eretz Yisro'el was established by the Talmidim of the Gr'o and Talmidei Ba'al Shem Tov, and both according to the Gr'o and the Chassidic Minhag one doesn't put on Tefillin on Chol Hamo'ed, therefore the Minhag in Eretz Yisroel which is practiced by almost everyone is not to put on Tefillin in Eretz Yisro'el, (the Sephardim also do not put on Tefillin).