Hi @parissin ,
Unfortunately the [https://www.manualslib.com/manual/808550/Saeco-Hd8751.html?page=3&term=+board&selected=1|service manual] doesn't get down to that kind of detail. It only lists the part numbers for the various boards in the unit, not the components on the boards.
Is there any markings on the transistor itself which may help to identify it?
If there is any markings on it and you can’t work out what it means, post an image of the transistor showing the information (and the board) back here and hopefully someone may be able to help. Here’s how to do this.
[guide|21499]