The fullerides AxC6o (A denotes alkali metal dopants in fullerite C6o) are classified as isotropic "dirty" superconductors of the second kind with phonon mediated electron-electron pairing. In the proposed three square-well model the AxC6o is characterized by windows of low-frequency intermolecular phonons, high-frequency intramolecular ones and Coulomb energy ranges with cutoffs wet, ~Or~ and to c, respectively. For the reason of the inherent imperfections of fullerides the extremely short collision lifetime of electrons force one to assume the "impurity representation" and to include every cutoff frequency ~Ocr, OJr~ , WC in the starting equations of superconductivity according to the Anderson theorem for potential spinless scattering. The different energy scales lead to renormalization of the calculated coupling constant and to abandonment of intermolecular phonons for superconducting pairing in AxC60 due to the logarithmic terms of the Tolmachev-Bogoliubov-Tyablikov kind. To illustrate the usefulness of the suggested model of AxC6o the superconducting critical temperature (To) for conventional fullerides K3C6o and Rb3C6o, the carbon and alkali metal isotope exponents, and the pressure effect for T c are estimated.