Components or the Software problem?
If there is a complaint with an electronic equipment, one will usually tackle the fault by looking for bad components. There is no doubt that components give lots of problems such as bad/bulged e-caps, shorted semiconductors, open/high ohm resistors, bad fuse and etc but you also have to take into consideration of beside bad components, software or firmware/programs in the IC could corrupt or lost.
If you just concentrate on the components then chances is high you will not be able to solve the problem because the real culprit is due to corrupted data in the ICs. ICs such as ROM/FLASH Rom, EEEROM or ROM that built into the MCU IC could lots its data and you need to reprogram it back in order for the equipment to work. You may also have to take note that sometimes both the components and the firmware could have problem. This means when someone have solved the power problem the equipment would still not work because the programs inside the IC have problem.
Nowadays I can say many electronic equipment are using MCU/ROM/EEPROM in the mainboard and if the programs inside already corrupted you will have a hard time to troubleshoot the problem because you might have guess that the problem is bad components. So, be extra alert of such problem in today's equipment.
Conclusion- If you found all the components in a circuit board to be good the next step for you to troubleshoot/check is to suspect bad programs in the ICs.