Technomate TM 5000D help?

I was given above model receiver, the unit poweers but when connected to the dish there is no signal I checked and there is no voltage to the LNB I visually checked the main board and the is a heatsink mounted device pcb marking U12 which is blown the device is markes as 317 JRC M2042G I cannot find any reference to this number I would guess it is a power regulator of some sort ... Please can you help to what it isand what can be used to replace it. Thanks & Regards Alan