If it was working fine when you shut it off, then doesn't work at all the next morning, with no service in between and no puddle of fluid below then I would suspect either something broke or something is stuck.
For example, if the lift spool valve is stuck in, say, "float" then the 3ph won't lift. That might happen if a screw fell out in the joystick mechanism. If the FEL relief valve is stuck open then no pressure can build up in the hydraulic system. If the hydraulic pump or pump drive broke then there will be no hyraulic pressure. (The HST uses the same fluid sump but has it's own separate pump system).
Just to add to what Torch said.
My B2910 is the same tractor as yours, with a few deluxe features.
One time I was having an issue related to hydraulics. Don’t remember the details, but after posting a question, someone suggested I check my 3PH lever. (I had my 3PH backhoe on at the time). Like you, worked fine the day before, but not the next day.
Well, it turned out I had some how moved the 3PH lever up to the full raise position, and it must have activated a pressure relief valve. Moved the lever to the proper full down position with the backhoe attached and the problem went away.
So MAYBE as Torch indicates your problem MAY have a simple solution like mine did...
