hurco km3 text screen got off changing bu407d but....

[junaid.wahid]

hi, all
i have km3 ultimax2 the text screen has got off i chenged transistor(bu407d)
wich was heated up screen works all right for 2 days and then got off again can anyone help me ?

[bloke]

I don't have any schematics for these displays as they were supplied as an assembly. It may be the line transformer failing.