Where is the processor located?

To begin from the beginning: Using flashlight turned on for about half a minute on my nexus I dropped it from 1 meter height, the backcover and battery came apart. No visual damage to the screen or body at all. After assembling it the phone never turned on. No indication of charge when connected via USB cable to a charger or computer. No effect when removing and inserting the battery with connected USB cable. The repairman told me the electric contact between the processor ball grid array and the mainboard socket might be damaged due to such a drop. He also told me he has no suitable stencil to re-attach the processor. I asked him where the processor is located and his answer was - on the motherboard's back side and the only way to get it work is to get him a broken phone or a working motherboard to assemble a working phone. But I failed to locate the processor there using your pictures in Step-by-step Guide. What would you advise?