Mother logic board has some power issue, how to fix?

I have some power issue in my logic board of HP deskjet 1055. I checked it by Multimeter and see it has a faulty diode and all the capacitors,resistor and IC are ok? I don't know what is the problem there can't find it. If u can tell the reading in 30volt dc input and unable to shortlist the problem . Faulty diode is PJ028S SS16 is this may be power issue?