Does the M1 series tank have the means for the crew to manually transverse the turret and elevate and depress the gun? An EMP event could fry the electronic and electrical circuitry and controls for the engine and other power sources.
Of course not.
However, if the designers don’t take into account the fact that the system may fail, by one means or another, then they will make the tanks and tank crews vulnerable.
The whole system should default to some basic mode that will allow some minimal function. It could be purely defensive such as being able to drive the tank to a safe place for repairs.