You can use a basic and inexpensive multimeter to check the PSU rails by measuring the voltages across various connectors of the power supply. It is also used to check the connectors of the PSU and whether they are outputting proper voltages. If the voltage levels are significantly lower or h...
I recently came in front of bad notebook computer main board, which main failure was due to a bad smd tantalum capacitor. It serves as output of the graphic card power supply, is around 220-330µF 2V-2.5V you measure the voltage on it, and get 0.3V and you should get around 1V...