calling all dual experts - i need help

i have just picked up a Dual 1215 at a garage sale and i've cleaned and relubed and oiled it but i am stuck with one last (i hope) thing... the cam doesn't engage when using the autostart to advance the tonearm... i initially thought this was the infamous Steuerpimpel problem but it is not... i just have to nudge the cam and then it engages, the tonearm moves onto the vinyl and it all works fine... i've read the manual and still cannot figure out how to remedy this (without the nudge) and i don't really want to replace the cam as it looks fine ( all teeth etc)... i am thinking i am either missing how to set the cam (put it in the right place so it engages each time) or a part that i've missed just needs that few "mm" adjustment.... any and all help to end my frustration is appreciated