This is a poorly EMtest VCS500N, an 8kV three phase 1.2/50us surge generator with no output from its coupling network 😢!
The fault was traced to a couple of dry joints on the coupling network driver board. Took a bit of finding, but it's raining here today and I have lots on as usual so thought I would take a look this morning and it turned into a few hours work!
For those of you interested in the internals:
Main switch is bottom right - This is an EM test propriety switch, fully potted.
Driver board for the three phase coupling network just above it.
Not measured, but pretty sure are the green resistors bottom back - these form the 2R source impedance of the generator.
Power supply back left and main control board top front.
Just need to put it all back together and sort the calibration. Hopefully there will be no screws left over 🙂.