Thom,
Another question: did you have the tubes in when you made the voltage measurements? Did you check the posted corrections to make sure you have the latest information from where the manual had some errors?
Yes, it is completely possible to short something out with a test probe when measuring, but the thing that is really odd, if I'm reading things correctly, is where are the voltages coming from if the fuse was blown? Things just don't seem to be adding up here.
-- Jim