I can relate to that. The magnet that holds the pto in place is a common failure on those, but do is the relay in the hold in circuit, which is also a lot cheaper than the magnet to start with. Good luck.
I just posted about my F935, the PTO shuts off after about 15 minutes. You mentioned a magnet and a relay in the hold-in circuit- is that in the PTO Clutch assembly? Would that apply to mine as well?