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How To Check A Circuit Board For Faults

How To Check A Circuit Board For Faults

A circuit board is a major component in all electronics and electrical instrument. It has changed the world forever. However, a faulty printed circuit board is prominent, even if you are not using it for technical requirements. 

So, for the proper use of your instruments, it is beneficial to know how to check a circuit board for faults. A circuit board is made of many components, and so, an array of defects may appear on the board diameter. 

Generally, you will see the below-mentioned faults in a circuit board-

  • A brunt circuit component 
  • Fluid leakage 
  • Connection shorts in the PCB
  • Power related issues 
  • Soldering problems

Although the list may seem a long one, you can quickly check the faults with a multimeter. So, we will discuss the methods of using a multimeter to inspect the PCB for electrical faults. 

How To Check A Circuit Board For Faults

A multimeter is a piece of dependable equipment to check for shorts and electronic faults almost in all electrical devices. Using the multimeter circuit board, you can inspect for resistance, capacitance, current, fuse shorts, AC and DC voltage, etc. 

Since it performs so much testing jobs at once, it is widely known as a combination of multimeter, ammeter and voltmeter. 

Before you can use a multimeter for the electronic fault finding methods, it is necessary to go through two more inspections of the printed circuit board. These are:

Method 1: Visual Inspection

Thorough visual checking of the entire circuit board will reveal any burnt or damaged components at ease. The burnt and eroded component is a sign that there are either chemical fluid leakages or severe overheating issues on the board. Also, it signals the most apparent reasons for a PCB malfunction. 

Method 2:  Physical checks

You can find more useful and practical insights into the malfunctioning PCB with an in-depth physical inspection.  It is helpful to identify the burnt or damaged components, which otherwise would be impossible with visual inspection only. 

You can use an oscilloscope for even better results. 

Method 3: How to check PCB with multimeter PDF

Suppose you want to check for the major problems or faults in a circuit board such as glass PCB or ceramic PCB. The best part, you don’t need to be an expert for using a multimeter to check for the shorts and fuses on the PCB.

Step 1:

Before you start examining the PCB for any malfunctions, could you turn it off for safety precautions? Find the AC outlet and disconnect the cord from it. It will ensure there is no direct electricity supply in the PCB anymore. 

Step 2: 

Start with the checking of the fuses of the circuit board. You can use nose pliers to pull out the fuse and check for its damage. Also, check the filament inside for a glass fuse.  You will see a broken filament within a damaged fuse. 

You will need to use the multimeter to check the ceramic fuse. At first, set the multimeter promptly in the continuity function. Then, touch the probes of the multimeter with the metal ends of the fuse. If the fuse is in ideal condition and continuity, the meter will beep. 

Step 3: 

Once you have checked the fuse, you may proceed to inspect any shorts in the PCB. Although at times, people say the steps of how to test a circuit board for a short is complicated, you can quickly accomplish it with a multimeter. 

Connect the multimeter socket with the multimeter ‘s lead plug. The lead plug is colored red for easy identification.  The black colored lead plug needs to be connected with the ‘COM’ socket. Finally, set the multimeter effectively in its continuity test. 

The continuity test position is easily identifiable with a diode icon and few parallel lines on the multimeter display. 

Step 4:

This is the continuation of the shorts finding procedure on the PCB. At first, please turn on the multimeter and check its continuity position. If appropriately set, the multimeter will beep when you connect the two probes (lead plugs). 

If you fail to hear any beep sound, it may be due to either of the following reasons:

  • The continuity position isn’t set correctly. 
  • The multimeter battery is finished and needs replacement. 

Once you sorted the issue, check for the continuity position again. If all goes planned, you can quickly proceed to the next step. 

Step 5:

Now connect the two probes with the first and last position of the problematic trace. Many people say you need to touch the negative pole of the multimeter with connector and positive pole with the NPN transistor base. 

However, it doesn’t matter. No matter, which probe is connected with which end, you will get similar readings. You need to press the probe firmly with the traces to set the electrical connection correctly. 

A beep sound means there are presences of shorts in the PCB trace. You may repeat the process for all the susceptible traces. 

Step 6:

Now, you can check the wires and cables attached with the printed circuit boards. At first, set the digital multimeter in ‘resistance’ mode. 

Then, connect the two terminals of the multimeter with the cables and wires. Check the readings. An ‘OΩ’ suggests that the cable connection is in good condition. On the other side, ‘infinity’ reading means the cables are malfunctioning. 

What to Do With a Faulty PCB?

A faulty PCB may be hazardous for all types of electronics devices. So, you need to either repair the damaged circuit board or replace it with a new one to avoid any hazards from the damaged parts according to the Environmental Protection Agency (EPA). 

So, it is recommended ardently that you consult an expert electrician to replace the circuit or the copper traces with shorts for the proper functioning of the unit. 


 A printed circuit board is made in a smaller copper trace and is connected with precision. So, even the slightest defect may ruin the whole device. That’s why for user’s safety and long-lasting performance of devices, you should know how to check a circuit board for faults. 

And when you identify any malfunctioning, you can quickly resolve it on your own or consult an expert for further assistance. 


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