  We examine the cosmic microwave background power spectrum for adiabatic
models with a massive neutrino component. We present the results of a detailed
numerical evolution of cold + hot dark matter (CHDM) models and compare with
the standard cold dark matter (CDM) spectrum. The difference is of order
$5-10%$ for $400 < l < 1000 $ for currently popular CHDM models. With
semi-analytic approximations, we also discuss the relevant physics involved.
Finally we remark on the ability of future experiments to differentiate between
these models. An all-sky experiment with a beam size smaller than 30 arcminutes
can distinguish between CHDM and CDM if other cosmological parameters are
known. Even allowing other parameters to vary, it may be possible to
distinguish CDM from CHDM.
