That's right David.
The Norelco units were made in the Netherlands.
As far as I know the 799 also used a Schmidt optics with an MW6 CRT.
The optical box was a bit different from the later cast units.
The pre-war Philips did not have the Schmidt optical system.
Is was a projection tube with lenses in front of it.
That indeed seems to have used a 4" tube @ 25kV.
Jac
EDIT: at some time (probably 1936) Philips made a hollow front projection tube as well.
Never seen one in the flesh.
