power problem with dcc

Hello people new to the sight so here is my first post and problem.Brought a prodigy 2 at warley the weekend and a dcc ready class 66 i've since fitted a tcs m1 decoder and all seems fine,occasional stuter around one bend but i can live with that,now i have a simple very large loop 25 foot by 10ft its in the loft now to this i've added a sid ing.The problem is when i manually flick the point the train stops! and i just get a buzzing noise every so often and the train slightly moves? now i'm useless at wiring and haven't a clue really so any help appreciated. Its 00 gauge ,peco code 100 track and streamline points. I'm sure its due to wiring but i haven;'t a clue!! thx