SA ??? monitor

  • Who can tell me about following monitor.
    SA model XDM-5050
    Fcc id:MM9XDM-5000
    Somewhere on the net I found MITSU XDM-5050 (the same ???)
    The set is equipped with several ON4980 transistors.
    One is shorted between Base and Collector.
    With the transistor removed the HV is present as well as the raster.
    The 2sc4980 seems to be a replacement ( SHINDENGEN ).
    Are there maybe any other replacements possible?
    All suggestions or schematics are very welcome.
    Thanks,
    Muhtreen