Yes could be vertical output transistor, most likely... But could be Vcc for the vertical which is supplied by the flyback.
It is rectified by D304, look for 18 volts at L401/C402.
If you need a schematic, visit my website and go to the standard res CRT monitor. It is a generic schematic for the same board that I use.
Hope this helps, but feel free to contact me direct phone or e-mail below.
By the way we can also offer you a quote to repair the board.
Good Luck
Rick Nieman
www.niemandisplays.com519-621-1722