Like anything in troubleshooting, it will require some knowledge of the operation of the power supply type in the unit and ability to trace problem from what is known to be good towards the trouble spot.
At the moment, without any schematics and a report of what you have tested so far, (point to point) it really is like how long is a piece of string.
Nothing here for us to go by in the way of diagrams, photos, etc etc.
It could be somethings as simple as a crook switch, a broken plug or socket to a faulty smps, the latter of which not many newbies would have a clue on which way to go.
I doubt there would be any kind of "reset" in this, it's not really like a pc or a gameboy.
