[SOLVED] Metronome

I am trying to get acurate beat grids for some of my tracks, traktor is very good at beat griding my tracks apart from the odd few here and there, so i am trying to use the metronome to beatgrid the tracks but nothing seems to happen, i cant hear any metronomme click, and even when i move the beatgrides way out just to check it, i would expect to hear clapping like a beat being out but still nothing, is there a secret way that i havent found to turn it on,

i am clicking the metronome in the corner

clicking tick

and clicking the headphones buttons within traktor but still nothing

does it only work when you are using and external mixer?

i am using traktor 2.5 scratch pro 2