[en] The calculations of a system for deflection of a beam from the chamber of isochronous cyclotron U-120K, which accelerates protons (11-40 MeV), deuterons (6-17 MeV) alpha-particles (11-35 MeV) and helium-3 ions (15-45 MeV). are reported. The deflecting channel consists of the electrostatic, electromagnetic, and current sections. The parameters of channel sections, configurations of electrodes, current coils and ferromagnetic plates ensuring the required electric and magnetic fields are given. The calculated beam extraction efficiency is shown to be ≥80% for the whole range of the accelerated particles. Beam losses in the channel do not exceed 10%. 7 refs.; 9 figs.; 3 tabs