Depressurized pressure tank - how to pressurize again
The tank should be empty but with no air in the bladder the water may not have been pushed out. It sounds like your compressors not properly seating on the Schrader valve, I have filled pressure tanks with bicycle pumps in the past it takes a while but any pump should do the job if it has a standard valve stem adapter. Your observation that there is no pffft makes me think the supply side of that valve is not opening when attached to the tank.