iPad 3 screen repair - LCD/Motherbord

Hello,

my iPad 3's digitizer broke after falling for the 2-3th time. So i ordered a new digitizer to fix it. When dessambling the iPad everything went as the video told me it would, so i carried on.. I removed the LCD, i cleaned out the iPad.. But when reassembling and turning the power on to test it: iPad turned on > LCD didnt light on.. I know the iPad works because when i plug it in the PC it connects and everything.. So i was wondering whether the LCD or the motherbord of the iPad was broken? Because ordering a new 80euros LCD when its not broken is a little bit stupid..

Respond me asap please,

Thanks ahead!