I bought this the other year on Ebay for a ridiculously cheap amount of money, but I didn't manage to get any output from it when I tried it, so - I thought I'd take another look; after a bit of googling I found out the unit required an interlock fitted to the back to enable the outputs to work; not sure if this was retro-fitted sometime later as a safety feature? idk, anyway, it turned out you can defeat this by simply shorting pins 4 & 5 on the input port; so, after doing this, the unit seemed to work perfectly; the only issue was I don't have any the correct chunky HV test leads, so, I had to rig some quick and dirty leads up to it in order to test it.
Below are 3 pics showing the testing of a 68V bi-directional TVS Diode.
Below is a pic showing a low ground bond test current being measured on my DMM.
Below are a few tear-down pics I took last year.