The original 12.9-inch Pro, no longer charging - on a device this age the board is as likely a culprit as the port.
Service Details
The first 12.9-inch Pro charges over Lightning, and it is old enough now that the socket has usually earned its wear honestly. The tell is a cable that has to be held at a particular angle, or a device that charges from one cable and refuses another.
The port is soldered to the logic board, so this is bench work under a microscope rather than a part swap. We test the charging circuit at the same time, because on a device this age the board is as likely a culprit as the connector, and only one of the two is fixed by a new port.