My father recently passed away, can I deposit a check into our joint checking account without his signature

You don’t say how large the check is, which may help you decide how much work you want to do to be able legally to deposit it in an account or cash it. This check is now an asset of his estate and it is not yours to deposit or cash. In order to legally be able to deposit that check anywhere or cash it, someone needs to open an estate with the Register of Wills office in the county where dad lived, get appointed personal representative of his estate, obtain what ‘s called “Letters of Administration,” and use those “Letters” as the required authority to deposit or cash that check. Since it is an asset of dad’s estate, it will then have to be divided among his legatees as per his Will, if he left one, or among his heirs if he did not -- after approval of that distribution by the orphan’s court or register of Wills. If the check is $30,000.00 or less, then you only have to open a “small estate” which if done properly, may be completed (opened and closed) in only one visit to the Register of Wills. A Power of Attorney dies with the person who gave it -- so it is no longer effective at all. If he has a Will, he would have named a personal Representative in that Will.
--Anne LoPiano

Discuss this with the bank--they will probably allow you to deposit it since it is a joint account and they can tell you how to endorse it. If they won't you can go to the county courthouse to file to open up probate and ask if there is a simplified procedure for smaller estates. Soon after you file you will receive a document called letters testamentary that you can present to the bank and cash the check without any problem. Just for your information, the POA expired as soon as your father died. keith345@hotmail.com (Probate Researcher)