Hi,
A European PC with a CGA card will output 60Hz NTSC
video....
Whilst this is perfectly true, IIRC the IBM CGA monitor takes the "RGBI"
signal produced by the card, not the composite one.
I believe that the composite output was intended primarily for driving a
modulator to allow the use of an ordinary TV with the system.
Almost none of the "clone" CGA cards I've come across over the years support
the composite video output.
TTFN - Pete.