About Circuit Board
Not all circuit board are design to be removed easily for testing. Some of the board like the LCD Monitor board have the power IC soldered behind it and this make us difficult to test the signals. Well, you can always remove the board and turn the board but sometimes because of the output wires connection to the Mainboard are short, you will still have problem in testing it. Sometimes, with just a minor fault (accidentally touching on other components due to constraint of space) it may blow up the power board.
In order to solve this problem, what you need to do is to solder external wires to the critical points in the power supply. Just solder the wire to the supply voltage pin and output pin of power IC and you will know if it good or not when testing it with meter and scope. Actually you have the choice to choose whether to do it this way or just directly replace the power IC and check all the components in it, but because you want to understand more about the troubleshooting, i guess you have no other choice other than solder wires in the important points. You may use this method to apply on any boards that the meter probes hard to reach.