922B hydraulics

Hi, I have a 922B that had water in the hydraulic tank when I bought it.  I drained the oil and changed the filter & flushed it with more oil (low hour hydraulic oil from a new digger but clean).  It was fine for a while but now the lift control valve won't move.  The tilt is fine.  I have taken the lid off the hydraulic tank and the lift spool is not frozen, it will move very slightly.  Could it be a detent problem?
Any recommendations would be appreciated.

Does the auto kickout or positioner work? Maybe they are stuck on and stopping the spool from moving.

I wonder if there is a tiny piece of debris jamming the valve. A piece of debris that is small enough to not be visible can jam the valve. Blow some air around the spool to see if it will free up. Good luck.