What Region are the DVD's that play in black & white? Region 0 is a worldwide region that will work in any DVD player, so I reckon those DVDs could be NTSC but Region 0.
This means they'll play, but unless you use the right cable (as Harry said) they'll appear in B&W.
As a point of interest, a lot of porn DVDs are Region 0.... ummm, apparently... so I've been told.... anyway...
- S
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