VCR to TV signal problem

[lynniebear]

(Please forgive any gaffs, its my first post)
Ive just had to replace my tv (with a Dual 28" Widescreen) and when i play ANY videotape on ANY vcr through ANY scart, scart socket or rf lead i get 3 or 4 secs of the film then a 1 or 2 sec 'wiggle' (the sound is ok) and this keeps repeating. I have no probs with my dvd player or freeview and i have checked that the vcrs, tapes and leads function perfectly on other tvs. I'm hoping that there is a simple solution as i'm not looking forward to the trip back to the shop with this big, heavy tv.