The generator you need to repair is to the right of the main computer, i think you need 50 repair and some scrap metal to fix it, or you can talk to the robot upstairs with 70 science and get him to fix it.
I wondered what that robot was for (PYTHON was his name). Since I'd already done the repair, he didn't seem to have a purpose.
OP: After you reset the two computers outside, you go into the tower and work your way to the top where the mainframe is. Fix the generator beside it, activate the mainframe to configure the power grid, then go up to the outdoor observation deck to turn on the array (can only be done during daylight hours).