Question on Emerson 611

[Rich12]

Hi everyone over the summer I worked on a couple craigslist finds. Restored an echo 425 oscilloscope and finishing up a Hoffman T1919, as soon as I figure out the vertical issue. So getting to my question, after slow progress, it was in really bad shape, I'm starting the power up tests on my Emerson 611. I've pulled the HV rectifier tube, all tubes are lighting up until 92 volts when the isolation transformer trips? I've been checking soldering, wires , etc. but no luck yet. I wanted to see if anyone has some suggestions as to a likely place to look? Thanks!