6 Ways to Check for Short Circuits in PCB Boards!

August 4, 2025

First, let’s understand the common types of PCB short circuits:

1. Functional Classification:
Solder Shorts (e.g., solder bridges)
PCB Shorts (e.g., copper residue, misaligned vias)
Component Shorts
Assembly Shorts
ESD/EOS Breakdown
Inner-layer Micro Shorts
Electrochemical Shorts (e.g., chemical residue, electromigration)
Other Causes of Shorts

2. Routing-Based Classification:
Trace-to-Trace Shorts
Trace-to-Plane (Layer) Shorts
Plane-to-Plane (Interlayer) Shorts

1.Open the PCB design drawing with a PC, light up the short-circuit network, and observe which positions are the closest and easiest to connect together. Particular attention should be paid to short circuits inside the IC.

2. If it is manual welding, good habits need to be developed:
a. Before welding, visually inspect the PCB once and use a multimeter to check whether the key circuits (especially the power supply and ground) are short-circuited.
b. After each chip is soldered, use a multimeter to check if there is a short circuit between the power supply and ground.
c. When soldering, do not randomly swing the soldering iron. If the solder is thrown onto the pins of the chip (especially surface mount components), it will be difficult to detect.

3.A short circuit was found. Take a board to cut the wires (especially suitable for single/double-layer boards). After cutting the wires, power on each functional block separately and gradually remove them.

4.By using short-circuit location analysis instruments, for certain conditions in specific situations, the detection efficiency of the instrument equipment is higher and the detection accuracy is also higher.

5.If there is a BGA chip, since all the solder joints are covered by the chip and cannot be seen, and it is a multi-layer board (more than 4 layers), it is best to separate the power supply of each chip during the design and connect them with magnetic beads or 0-ohm resistors. In this way, when a short circuit occurs between the power supply and ground, the magnetic bead detection is disconnected, and it is very easy to locate a certain chip. Due to the high difficulty of soldering BGA, if it is not automatically soldered by a machine, a slight inattention may cause a short circuit between the adjacent power supply and the ground two solder balls.

6.When soldering small-sized surface mount capacitors, extreme care must be taken, especially power filter capacitors (103 or 104), which are numerous and can easily cause a short circuit between the power supply and ground. Of course, sometimes with bad luck, the capacitor itself may be short-circuited. Therefore, the best approach is to test the capacitor before soldering.

During circuit board maintenance, when encountering a short circuit fault in the common power supply, it is often a headache. This is because many components share the same power supply, and each component using this power supply is suspected of short circuit. If there are not many components on the board, the "hoeing the ground" method can eventually locate the short circuit point. However, if there are too many components, whether the "hoeing the ground" can accurately address the problem depends on luck.

To deal with the plug-in capacitors on the circuit board, you can use a diagonal pliers to cut off one pin (be careful to cut from the center, do not cut at the root or along the circuit board). For plug-in ics, you can cut off the VCC pin of the power supply. When a short circuit disappears when a certain pin is cut, it indicates that a certain chip or capacitor is short-circuited. If it is a surface mount IC, the power pins of the IC can be melted with solder using an electric soldering iron and then lifted up to keep them away from the VCC power supply. After replacing the short-circuit component, simply reweld the cut or lifted part.

There is another relatively quick method, but it requires a special instrument: the milliohm meter.

We know that the copper foil on the circuit board also has resistance. If the thickness of the copper foil on the PCB is 35um and the width of the printed line is 1mm, then for every 10mm of length, the resistance value is about 5mΩ. Such a small resistance value cannot be measured with an ordinary multimeter, but it can be measured with a milliohm meter.

Let's assume that a certain component is short-circuited. When measured with a common multimeter, the resistance is always 0Ω, while when measured with a milliohm meter, it is approximately tens to hundreds of milliohms. When we measure with the test leads precisely placed on the two pins of the short-circuited component, the resistance value obtained will definitely be the smallest (because if measured on the two pins of another component, the resistance value obtained will also include the resistance of the copper foil traces on the circuit board). In this way, we decided to compare the resistance values of the milliohm meter. When the resistance value of a certain component (the same applies if there is a short circuit in solder or copper foil) is the smallest, then that component is the key object to be suspected. By deciding on this key point, one can quickly identify the obstacles.