For the lack of A output - check the A output against other "common" outputs on this ZW instead of against the "common" output in physical line with the A output. It is not uncommon that within the ZW the strip of metal connecting the 4 common outputs together becomes disconnected from individual "common" outputs.
This. I've wound up repairing ZWs by removing the posts that have broken off the bus strip and replacing them with 4-40 bolts through the strip, held down with nuts on the outer case...
(note the nuts on the upper terminals)