Ironic i got one in today with no head action, mine is yoke cable, looked behind the ball assembly and the brown blue is out of its black sheath and copper showing so assume its knackered with no ~v on outlet.
Hate doing these as the main motor has to come out to replace the yoke cable.
A few pics here for you, pop the lhs wheel cover off and the peg is pictured, sounds like its jammed solid (no suction cause too) if the head cant be removed ? You should just push both grey buttons in and pull away - try a bit of force ?
Careful, may be full of solid cat shit !
Just repaired a 32" monitir with led faults for a regular commercial customer of mine too.