Selection guide for common tools for circuit board repair

Selection guide for common tools for circuit board repair

In circuit board maintenance, choosing good tools and making good use of these tools is the premise of ensuring the speed and quality of maintenance. Today, I will introduce the tools commonly used in circuit board repair.

1. Hand tools

Commonly used hand tools for circuit board maintenance include screwdrivers, tweezers, needle-nose pliers, wire strippers, diagonal pliers, wrenches, files, craft knives, magnifying glasses, and circuit board welding aids, etc.

Depending on the size and specification, screwdrivers are divided into character batches, cross batches, plum blossom batches, etc. When disassembling and assembling screws, choose the most suitable screwdriver. In addition, pay attention to the size of the screwdriver when tightening and loosening, and do not make the screw slippery, causing unnecessary trouble for disassembly and assembly.

The tweezers must be prepared in several sizes for different gripping components and for gripping the wires to facilitate soldering when soldering the wires. Shorter, harder, and rigid tweezers are used to pick up more significant components or lead tips; longer, softer, and less rigid tweezers are used to pick up smaller SMD components. ZEUS MINING Stainless Steel Anti-Static Tweezers 6-Piece Set includes 6 anti-static tweezers of different sizes and tips for everyday use in precision equipment.

The craft knife is used to scrape the oxide layer on the surface of the component pins, cut off the unnecessary copper foil traces, scrape the oxide layer on the surface of the circuit board, and scrape the green oil on the surface of the copper foil traces of the circuit board, exposing the shiny Copper foil surface, easy to connect during maintenance. Suitable for various model making, etching, engraving, degumming, and restoration work.

Vise can be used to hold screws with split screw heads for easy loosening; needle-nose pliers are used for clamping small parts such as screws and wires; diagonal pliers are used to cutting wires and component pins that are too long after welding; Wire pliers are used to stripping the plastic skin of wires; copper-nosed pliers are used to crimping the copper-nosed connectors of cables.

In addition, a magnifying glass is used to facilitate the observation of the model of small components, the soldering situation, and the small traces on the circuit board. In addition, circuit board cleaning solutions, anti-static brushes, and other circuit board dust cleaning tools are also required.

2. Multimeter

Multimeters are divided into two types: pointer type and digital type. One of the most commonly used is the digital multimeter.

Features of digital multimeter: the digital display of test results, relatively accurate; automatic gear change, no need to switch gears frequently; intelligent control of single-chip microcomputer, which can add many other useful functions; high input impedance, small impact on the circuit under test during testing, but the multimeter The internal circuit is easily disturbed relative to the pointer meter. For example, the measurement data may be inaccurate in the case of large harmonic interference.

3. Digital bridge

Digital bridges are also called LCR bridges. Without powering on components, you can test their impedance characteristics at different frequencies and display their characteristic parameters, as shown in the figure below (digital bridge). The resistance, capacitance, and inductance components we use are not ideal pure resistances, capacitances, and inductances. Because of their inherent characteristics and technological differences, their characteristics at different frequencies are not the same. These characteristics cannot be tested with a multimeter because the excitation signal is not an AC sine wave signal of various frequencies such as a digital bridge, so it is powerless to test the frequency characteristics of components.

In circuit board repair, the following functions of the digital bridge are beneficial for finding faulty components.

1) Test of capacitance;

2) Test of resistance;

3) Testing of inductors and transformers;

4) Impedance comparison to find faults.

4. Circuit board desoldering tool

Soldering and disassembling components are regular work in circuit board maintenance. The selection of high-quality desoldering tools and correct operation methods are the premise of ensuring the quality of maintenance.

Desoldering tools commonly used in circuit board maintenance include electric soldering irons, constant temperature soldering stations, hot air soldering stations, and tin removers.

The characteristics of high-quality electric soldering iron are: long life of heating core and soldering iron head, good compatibility between soldering iron head and soldering tin, the stable and controllable temperature of soldering iron, and anti-induced electric and anti-static functions corresponding to different solder joints, soldering iron head also can be replaced. Therefore, electric soldering irons are frequently used in maintenance work. It is best to use long-life temperature-regulated electric soldering irons for industrial use and have a structure with replaceable soldering iron heads.

The tin removal wire is a mesh braided wire made of soft copper wire, which is used to absorb the heated and melted solder. The thin wire can be used as the connecting wire to the broken wire, and the wire with different wire diameters can be selected according to the current on the circuit board.

Soldering and dismantling of SMD components are suitable for using a hot air soldering station. The hot air welding station realizes the welding function through air heating and comprises the air pump, air pipe, heating core, handle, temperature control circuit, and other components. After the soldering station is powered on, the air pump works, and the air is blown out from the air outlet of the handle through the air pipe. There is a heating core and a temperature sensor in the handle. The heating core heats the blown air, and the temperature sensor detects the temperature of the blown air. The soldering station has a knob to control the temperature and a knob to control the amount of airflow.

The BGA rework station is the special equipment for BGA chip desoldering, which can provide uniform heating of the upper and lower layers of the BGA part of the circuit board and has an intelligent and controllable temperature change curve to ensure the quality of BGA chip desoldering.

5. Adjustable power supply for maintenance

The circuit board is inseparable from the power supply part. Many circuit boards as part of the whole machine do not include the power supply part. A special power supply module provides its power supply, and the power supply module supplies power to it through terminals and leads. Generally, the digital circuit on the circuit board has a supply voltage of 5V or 3.3V, and the analog circuit is ±5V or ±12V or ±15V. Therefore, it is necessary to observe the fault phenomenon of the circuit board to be repaired or detect the maintenance effect and add the appropriate voltage. In addition, perfect overcurrent protection measures are required for the power-on circuit board, and the fault cannot be further expanded due to the overcurrent of the power supply. Therefore, preparing a DC power supply with multiple outputs and adjustable voltage and current is more convenient.

6. Signal generator and oscilloscope

An ordinary signal generator also called a function generator, is an active tool with adjustable output waveform, frequency, and amplitude. In addition, there are signal generators dedicated to maintenance, which can output DC voltage and current signals for testing and simulate thermal resistance, thermocouple, etc.

The function signal generator can generate a sine wave, square wave, sawtooth wave, and other signals of different amplitudes and frequencies. Sometimes it can be used as a driving signal to inject into the circuit board to test the response characteristics of certain chips or circuits, such as testing the frequency of certain chips. In addition, it can be used in conjunction with the oscilloscope to observe the signal waveform.

When using the oscilloscope, you should pay attention to the highest voltage that the oscilloscope can test. If the measured voltage exceeds the highest voltage of the oscilloscope, the oscilloscope may be damaged. In this case, an oscilloscope high-voltage probe can be used to test the signal after attenuation.

7. Transistor tester

In circuit maintenance, the transistor tester is mainly used to test the withstand voltage of diodes, voltage regulators, triodes, field effect transistors, IGBTs, capacitors, etc. It can also test the magnification of the triode and judge its pin conditions. For diodes, Zener tubes, and triodes of unknown types on the circuit board, the withstand voltage parameters can be understood by testing, which provides a basis for finding replacement components. In addition, some IGBT modules are damaged due to reduced withstand voltage performance. Therefore, you can use a transistor tester to test the withstand voltage value. Before replacing the IGBT, you can also measure the withstand voltage value to confirm that it meets the requirements.

8. PICKit 3.5 Programmer

The PICKit 3.5 programmer is used to read and save the hash board PIC chip data, and the PIC chip stores the hash board chip and voltage data. If the PIC chip data of the miner hash board is damaged or lost, the hash board will not work. This is because different miners need corresponding PIC files, and the PICKit 3.5 programmer must be programmed with a programming tool.

If the program of the PIC chip is lost or damaged during maintenance, and there is a chip with the same program on hand, the program writer can be used to copy it.

9. Online maintenance tester

The online maintenance tester is a component detection tool in a power-off state. The principle is that a sinusoidal AC signal source is generated inside the instrument. The signal source has a certain amplitude, frequency, and internal resistance; take the real-time voltage on the component as the abscissa and the current as the ordinate to make a plane curve, the VI curve. Different components or component combinations will result in different curves. If components have performance degradation, information can be obtained from these curves, providing helpful information for fault finding.

Appropriate tools have little damage to the circuit board, and guarantee the speed and quality of maintenance. Do you have any other recommended circuit board repair tools? Welcome to leave a message to recommend.