  We have constructed a visual light curve of the symbiotic star MWC covering
the last 87 years of its history. The data were assembled from the literature
and from the AAVSO data bank. Most of the periodic components of the system
brightness variation can be accounted for by the operation of 3 basic clocks of
the periods P1=19000 d, P2=1943 d and P3=722 d. These periods can plausibly,
and consistently with the observations, be attributed to 3 physical mechanisms
in the system. They are, respectively, the working of a solar-like magnetic
dynamo cycle in the outer layers of the giant star of the system, the binary
orbit cycle and the sidereal rotation cycle of the giant star. MWC 560 is the
7th symbiotic star with historical light curves that reveal similar basic
characteristics of the systems. The light curves of all these stars are well
interpreted on the basis of current understanding of the physical processes
that are the major sources of the optical luminosity of these symbiotic
systems.
