Earlier the theory of finite-gap integration was successfully applied to finite-component systems only. In this paper, we consider a first example of infinitely many component integrable systems. We construct multi-phase solutions for integrable dispersive chains associated with the three-dimensional linearly degenerate Mikhalev system of the first order. These solutions are parameterised by infinitely many arbitrary constants. As a by-product, we describe multi-phase solutions for finite-component dispersive reductions in these integrable dispersive chains.