The solution to the PTO problem on the Massey Ferguson 1839 baler will depend on the specific symptoms and problem. If the PTO unit is turning but not engaging the baler, it may need to be adjusted. If there are problems with the power supply to the device, the wiring may need to be examined and replaced. A clogged or damaged pump may also cause issues, as may worn or broken parts. In any case, it is recommended that you contact a qualified technician or authorized Massey Ferguson repair service center to examine and diagnose the issue in order to determine the best course of action.