PCB Factory: How to Overhaul the Circuit Board?
In recent years, the level of automation in machinery and equipment has significantly increased, leading to a surge in the number of embedded boards across various industries. When these embedded boards become damaged, the high costs associated with dismantling and replacing circuit boards have become a major concern for companies. So, are you familiar with the methods for repairing circuit boards? What is the typical repair process for circuit boards? Let’s take a closer look, as explored by the web editor.
### Classification of Circuit Boards
PCB circuit boards are categorized based on the number of layers they have. They fall into three main types: single-sided aluminum substrates, double-sided boards, and multi-layer high-density PCB circuit boards.
1. **Single-sided Aluminum Substrate**
In its most basic form, a PCB has components placed on one side, while the transmission lines are concentrated on the other side. Since the transmission lines appear only on one side, this type of PCB is referred to as a single-sided PCB circuit board. Single-sided aluminum substrates are generally straightforward to manufacture and have low engineering costs. However, their limitation is that they cannot be used for more complex products.
2. **Double-sided Board**
A double-sided board is an extension of the single-sided aluminum substrate. When single-sided wiring is insufficient for electronic equipment, a double-sided board should be used. It often features copper plating and wiring on both the front and back sides. The connection between the two layers can be established through vias, allowing for the necessary data connections.
3. **Multi-layer Board**
A multi-layer PCB is a printed circuit board composed of three or more conductive layers, with insulating materials placed in between. The conductive layers are interconnected in a specific manner. Multi-layer high-density PCB circuit boards are increasingly used in applications that require high-speed operation, intelligence, compact size, lightweight, and thin profiles in modern electronic technology.
PCBs are also categorized by their characteristics into flexible circuit boards (FPC), rigid boards (PCB), and rigid-flex hybrid boards (FPCB).
### Circuit Board Inspection Methods
1. **Needle Bed Test Method**
This method uses a yellow electrode connected to each test point on the circuit board. The spring mechanism ensures that each electrode exerts a working pressure of 100-200g to maintain good contact at every inspection point. The collection of these electrodes is referred to as a “needle bed.” Under the control of software, test points and data signals can be programmed, enabling the tester to retrieve information for all test cases.
2. **Circuit Board Observation**
Due to the lightweight and structural nature of circuit boards, professional technical equipment is required for proper observation. Typically, a handheld video microscope is used to inspect the circuit board’s structure. With the monitoring camera of the video microscope, the circuit board’s microstructure can be clearly visualized through the optical lens. This method allows for effective circuit board design and inspection.
3. **Two-Electrode Flying Probe Test Method**
The flying probe tester operates independently of any pin patterns installed on a fixture or support frame. Using system software, 2 or more electrodes are mounted on small magnetic heads that can move freely in the X-Y plane. Test cases are quickly generated from CAD or Gerber data. The two electrodes can move as close as 4 mils to each other. Each electrode can move independently with no real limit to their proximity. A detector with two movable arm-shaped probes is used to accurately measure capacitors. The circuit board is tightly pressed and placed on a metal cable sheath as one piece of the capacitor. If a short-circuit fault exists along the path, the capacitor will show a higher value at the faulty point.
4. **Visual Inspection**
When a circuit board arrives for repair, the first step is to inspect its appearance carefully. If the board appears burned, ensure the power circuit is normal before connecting it to avoid secondary damage. Visual inspection is a static method of data collection. The typical process involves several steps:
– Step 1: Check for any damage caused by human factors.
– Step 2: Look for burnt electronic components on the board.
– Step 3: Inspect integrated circuit chips.
– Step 4: Check if any wiring has been peeled, burned, or short-circuited. Look for copper pads that may have lifted.
– Step 5: Examine protective components (fuses, thermistors) for any blown fuses. If the fuse is too thin to see, use a digital multimeter to check for continuity and confirm whether it’s damaged.
5. **Static Data Measurement Method**
For most circuit boards, visual inspection may not reveal issues. In cases where parts of the board are physically deformed, a digital multimeter can be used to measure key components accurately and identify faults. Before measuring, it’s essential to determine if the power circuit operates using digital or analog signals. This discussion focuses on the static measurement method for digital circuits. The steps for maintenance are as follows:
– Step 1: Use a digital multimeter to check for short circuits between the switching power supply and ground.
– Step 2: Measure diodes with a multimeter to verify their normal operation.
– Step 3: Use the multimeter’s resistance function to test capacitors, checking for short circuits or faulty conditions. If issues are found, investigate whether the components or the connected power circuit are faulty.
– Step 4: Use a digital multimeter to measure integrated circuits, transistors, resistors, etc., and ensure they meet the expected logical characteristics.
**Tip**: After completing visual and static data measurements, most circuit board issues can be resolved. A key consideration is to ensure the switching power supply is functioning properly to prevent secondary damage during subsequent steps.
6. **Automatic Measurement Method**
The automatic measurement method is typically employed by manufacturers that produce circuit boards in high volumes. These manufacturers often set up general adjustment and maintenance platforms that can display key parameters, such as the status of switching power supplies and other essential raw data signals. The automatic measurement method addresses two main concerns:
– First, it categorizes the issues identified during the previous inspection steps and isolates the faulty electronic components.
– Second, if issues remain unresolved, the automatic measurement system can identify common faults by comparing the good and bad circuit boards. Based on this comparison, problems can be detected and corrected.
In recent years, the level of automation in machinery and equipment has significantly increased, leading to a surge in the number of embedded boards across various industries. When these embedded boards become damaged, the high costs associated with dismantling and replacing circuit boards have become a major concern for companies. So, are you familiar with the methods for repairing circuit boards? What is the typical repair process for circuit boards? Let’s take a closer look, as explored by the web editor.
### Classification of Circuit Boards
PCB circuit boards are categorized based on the number of layers they have. They fall into three main types: single-sided aluminum substrates, double-sided boards, and multi-layer high-density PCB circuit boards.
1. **Single-sided Aluminum Substrate**
In its most basic form, a PCB has components placed on one side, while the transmission lines are concentrated on the other side. Since the transmission lines appear only on one side, this type of PCB is referred to as a single-sided PCB circuit board. Single-sided aluminum substrates are generally straightforward to manufacture and have low engineering costs. However, their limitation is that they cannot be used for more complex products.
2. **Double-sided Board**
A double-sided board is an extension of the single-sided aluminum substrate. When single-sided wiring is insufficient for electronic equipment, a double-sided board should be used. It often features copper plating and wiring on both the front and back sides. The connection between the two layers can be established through vias, allowing for the necessary data connections.
3. **Multi-layer Board**
A multi-layer PCB is a printed circuit board composed of three or more conductive layers, with insulating materials placed in between. The conductive layers are interconnected in a specific manner. Multi-layer high-density PCB circuit boards are increasingly used in applications that require high-speed operation, intelligence, compact size, lightweight, and thin profiles in modern electronic technology.
PCBs are also categorized by their characteristics into flexible circuit boards (FPC), rigid boards (PCB), and rigid-flex hybrid boards (FPCB).
### Circuit Board Inspection Methods
1. **Needle Bed Test Method**
This method uses a yellow electrode connected to each test point on the circuit board. The spring mechanism ensures that each electrode exerts a working pressure of 100-200g to maintain good contact at every inspection point. The collection of these electrodes is referred to as a “needle bed.” Under the control of software, test points and data signals can be programmed, enabling the tester to retrieve information for all test cases.
2. **Circuit Board Observation**
Due to the lightweight and structural nature of circuit boards, professional technical equipment is required for proper observation. Typically, a handheld video microscope is used to inspect the circuit board’s structure. With the monitoring camera of the video microscope, the circuit board’s microstructure can be clearly visualized through the optical lens. This method allows for effective circuit board design and inspection.
3. **Two-Electrode Flying Probe Test Method**
The flying probe tester operates independently of any pin patterns installed on a fixture or support frame. Using system software, 2 or more electrodes are mounted on small magnetic heads that can move freely in the X-Y plane. Test cases are quickly generated from CAD or Gerber data. The two electrodes can move as close as 4 mils to each other. Each electrode can move independently with no real limit to their proximity. A detector with two movable arm-shaped probes is used to accurately measure capacitors. The circuit board is tightly pressed and placed on a metal cable sheath as one piece of the capacitor. If a short-circuit fault exists along the path, the capacitor will show a higher value at the faulty point.
4. **Visual Inspection**
When a circuit board arrives for repair, the first step is to inspect its appearance carefully. If the board appears burned, ensure the power circuit is normal before connecting it to avoid secondary damage. Visual inspection is a static method of data collection. The typical process involves several steps:
– Step 1: Check for any damage caused by human factors.
– Step 2: Look for burnt electronic components on the board.
– Step 3: Inspect integrated circuit chips.
– Step 4: Check if any wiring has been peeled, burned, or short-circuited. Look for copper pads that may have lifted.
– Step 5: Examine protective components (fuses, thermistors) for any blown fuses. If the fuse is too thin to see, use a digital multimeter to check for continuity and confirm whether it’s damaged.
5. **Static Data Measurement Method**
For most circuit boards, visual inspection may not reveal issues. In cases where parts of the board are physically deformed, a digital multimeter can be used to measure key components accurately and identify faults. Before measuring, it’s essential to determine if the power circuit operates using digital or analog signals. This discussion focuses on the static measurement method for digital circuits. The steps for maintenance are as follows:
– Step 1: Use a digital multimeter to check for short circuits between the switching power supply and ground.
– Step 2: Measure diodes with a multimeter to verify their normal operation.
– Step 3: Use the multimeter’s resistance function to test capacitors, checking for short circuits or faulty conditions. If issues are found, investigate whether the components or the connected power circuit are faulty.
– Step 4: Use a digital multimeter to measure integrated circuits, transistors, resistors, etc., and ensure they meet the expected logical characteristics.
**Tip**: After completing visual and static data measurements, most circuit board issues can be resolved. A key consideration is to ensure the switching power supply is functioning properly to prevent secondary damage during subsequent steps.
6. **Automatic Measurement Method**
The automatic measurement method is typically employed by manufacturers that produce circuit boards in high volumes. These manufacturers often set up general adjustment and maintenance platforms that can display key parameters, such as the status of switching power supplies and other essential raw data signals. The automatic measurement method addresses two main concerns:
– First, it categorizes the issues identified during the previous inspection steps and isolates the faulty electronic components.
– Second, if issues remain unresolved, the automatic measurement system can identify common faults by comparing the good and bad circuit boards. Based on this comparison, problems can be detected and corrected.
