show me video for repair dc output not given by the PS

MY power supply totally not showing any DC output and i didn`t have any about idea about power supply how does it work. How does it protect from over voltage and short circuit.

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0