Can generalized Turing machines compute all reals?
Any machine model in which a machine can be described by a string over a fixed alphabet can only compute countably many things. Since there are uncountably many real numbers, all of these machine models fail to compute almost all real numbers.

In fact, the alphabet need not be fixed. It is enough that the alphabet is taken from some countable set of finite alphabets, for example $\{1,\ldots,n\}$ for every $n$.