tech damage missing pins u2 ic

i need to rebuild pads cant find trace need to make jumpers need some info which pad is which??? ie what is a1,a2 etc and where are the jumping points and if i have to remake pad whithout this info i cant follow trace further back to rebuild there is 36 pins 3 are damaged im qualified in electronics and electrical/mechanical engineering so have base knowledge just need a nudge in right direction also what do you use to find trace a pin ? also what magnification do you use on such a repair? please help