Necessities of SMPS power adaptors for your usage
If you have confirmed that there is a problem with the 5 volt line, then how do we detect this offender because there are many components like open frame SMPS connected to this line? TTL ICs, CPUs, EEPROMs, transistors, diodes and even small filter capacitors are all connected to the 5 volt line. None of these components can provide any power to the printer. You can remove each component lead (5 volts supply) in the main board and hope the short circuit goes away. Suppose if you start to filter someone from the filter capacitor pin and the short circuit is removed, we can say that the real culprit is the filter capacitor.
The real problem is that if the board has too many components and it will take you a long time, removing one pin at a time will solve the problem. Identifying the 5 volt pin supplied to the Spider IC with 100 pins or more is not easy. Many spider ICs have a supply pin of more than 5 volts. Some have 4 and some have 6 to 8 supply pins. Does this mean you have to check one pin at a time until you find fault in the end? Not only that, a lot of expertise is also needed to check a short circuit between the supply pin removal and the ground from the spider IC. If you are associated with a circuit board track, the main board may be considered out of repair with the open frame SMPS manufacturer. Even if you can fix a broken circuit track, it does not mean that you have solved the actual fault!
Have you noticed that extra problems when you try to find a fault? There must be a better way to deal with this kind of problem. Yes it is true that one can use the ESR meter to slowly transcribe the source of the short circuit. You can use the ESR meter to detect a short circuit on an electronic board by checking the actual track resistance. One probe connects to the ground and the other to the circuit line and if you move along the measurement path, you know you are going in the wrong direction! If the ESR value decreases as you move along the track, you're in the right direction. The problem is if the main board has two layers, then there are 4 or 8 levels? You could waste a lot of your time and try to find the real error using the ESR meter method. After explaining a lot about the problems, it's time to wait for the answer to how you can solve such a problem quickly.
Did you know that in addition to controlling the power supply, DC electronic circuits can also be used to troubleshoot and detect the smallest component in the motherboard? Assuming that the VCC supply line is made by some defective components, you can easily detect this with the use of a variable digital DC regulated power supply. If you don't have a digital one, you can always use it with an analog panel meter which is cheaper.