I went back to the junk shop, found one I hadn't ripped the assy
out of, and took it over to their test bench. The reason I didn't
see anything happen was I didn't wait long enough. It appears to
have a built-in delay of a few seconds before the HV comes on.
Just about everything from my first message was right.
400v >400v(focus) 46v COM ???
I still have no idea what the last pin is for. I looked at it with
a scope, and nothing seems to be happening on it. The thing runs
at around 22KHz.
I assume the last pin must be the cathode voltage supply, or they're
doing something else like a voltage divider on the 400v supply.
