Every time I've suspected that I may have a bad transformer, it's turned out to be something else. Usually a bad fuse holder.
That's why I check fuses through the fuse holder. I put one side of a continuity meter on one fuse solder lug and the other on the opposite solder lug with the fuse in the holder. If I get solid continuity, I know that not only is the fuse good but so is the holder.
I find an ohm meter to be much more useful than a volt meter. I'd check for any possible continuity (open circuit) issues before I would begin checking voltages. Because, the former is much more likely than the latter.