New to debugging. How to go about finding a mistake in this exponential voltage converter
I'm not sure what your theory of operation is, but the base of Q2 is grounded.  The common emitter junction won't go below -0.77V, because Q2 will supply plenty of current through its B-E junction.  That means Q1 will remain off as long as the U1.1 output is negative, which it will be unless the inputs sum to less than -5V to overcome the effect of the 5V supply biasing U1.1.  Clearly, as long as Q1 is off, U1.2 will be at roughly VEE, and there won't be any other signal propagating from input to output.