An H∞ output feedback control design is presented for mechanisms with backlash, under the presence of external perturbation. Using the static dead-zone model as a simpler model for backlash, the non-linear problem is cast in linear H∞ framework, seeing the backlash effect as a bounded disturbance in the extended L2 space (L2e). Experimental realization in an industrial emulator with backlash is carried out, evidencing an acceptable performance of the controller subject to external perturbation.