(sold) Fluke PM3394A Oscilloscope, broken PSU

[PartialDischarge]

For sale is a Fluke PM3394A Oscilloscope with a faulty PSU.
At turn on the fuse always blows. So long time ago I decided to try to repair it, changed the busted main NPN switch (BUW13A)  but it failed again, so something else must be bad.
I don't have the time to repair it, so I'm selling it now. The good news is that all schematics and working descriptions are available in the service manual, and the PSU is old style with few parts.

Can post more pictures of the inside if needed.