Page 1 of No picture playing DVD`s

Can someone please help, i have recently bought one of those cheap DVD players from Superdrug. All was fine until i swapped it over to play on a portable tv, when i try to play DVD`s all i get is the sound and no picture if i play VCD`s its fine i get picture and sound. I have put it back on my other tv and it works fine i have also used the same scart lead on both tv`s

Just a guess, but is the DVD being output as RGB video and the VCD as composite video?

I don`t see any reason why they should be different, but if the scart input on the portable is composite only...