You must get the missing piece from the team rocket grunt in Cerulean city.
Do you mean the Power Plant? Are you looking for the way to activate your radio in Kanto? That can be done at the Power Plant.
a piece of the power planet's generator
He is outside the power plant
in the power plant
zapdos is beside the kanto power plant
You can't.You have to surf.
you go to the power plant in the kanto reigon
Viridian forest, Power plant.
Walk around the power plant for a bit
get the missing part from cerulean gym,and take it back to the power plant and talk to that guy who boss of the plant.
fix the power plant and then get it from the guy in the brown hat
He's outside the Power Plant in Kanto. :D