As always - great care to be taken on any mains powered device, if you work on the mains voltage part.
I suggest at first to check the power supply (without connecting it to the mains) for obvious faults like open circuits, fuses, burnt trough resistors, shorted rectifiers.
then, I would check if there are any output voltages once the PS is connected to the mains - just checking generally the low voltage output area.
All this is non specific (I have no first hand knowledge of the PS in question) but has worked for me on anything from TV's to terminals to computers etc.