AC power is not required on the -200 if the engine bleed valve was left open at last shutdown. Battery bus provides electrical power for the start valve solenoid & ignition.
Ah, but you have a closed bleed valve? Call a ground engineer for a manual override. Afterwards, cross bleed starts are possible, but fairly noisy on the old gal since you've generally got to go to 75% or better N2 for adequate start pressure.