About Testing Power IC
If i come across any SMPS fault that has many bad components in it, i will not replace the components and retest the power supply. I would usually direct replace the power IC and retest the set. I don’t even test the input/signal of the power IC. The reason for it is simple, since there are so many components found to be faulty in the power supply section, chances is very the power IC will be out too. Direct replace the power IC and the bad corresponding components could save your time of testing.
If you have not done that before, i suggest you to change your procedure of troubleshooting SMPS and i believe you too can see the different. However, if the complaint is no power and you did not see any burnt or bad components in it then i suggest that you perform the voltage and scope testing.