Page 1 of NTSC Projector + UK DVD player = Can`t see a thing!

Anyone got any idea why, when I output a pure NTSC from my DVD via S-Video/composite connection to an NTSC projector, the brightness levels plummet? Is this a characteristic of NTSC? I`ve had the same problem with a Wharfedale 750 and (thought it was a problem with the player, but...) now with a Panasonic RV40, but have had no problems in the past with a Samsung 809 and 511. The projector doesn`t like PAL60, but for some reason perfectly accepted the Samsung output when set to AUTO (apart from cropping some 40 pixels off the edges - the reason I am so keen to work with pure NTSC). It`s all a bit too much for me to grasp. Any ideas?