Technical Information
Common electronic and electrical appliance repair methods
[ 11-11-2024 ]
The common repair methods for electronic appliances mainly include the following:
1. Inquiry inspection method
This is the most basic method for repairing household appliances. Before repair, the maintenance personnel need to carefully ask the user about the fault characteristics and causes of the fault. For example, when repairing a remote control failure, if the remote control has been dropped, the circuit board should be checked for component pin desoldering; if not, the crystal oscillator should be checked. This method helps maintenance personnel quickly locate the problem and avoid unnecessary disassembly and misjudgment.
2. Visual inspection method
The visual inspection method is also a common method for repairing household appliances. During maintenance, this method can be used to make a preliminary judgment on the fault location. This method mainly judges the fault location through listening, looking, touching, and smelling.
Listen: Use your ears to find the fault location and cause of the fault. For example, when repairing small appliances such as color TVs and microwave ovens, if you hear a "pop" discharge sound, you should check whether the high-voltage device is discharged to the ground; when repairing electric fans and range hoods, if the mechanical noise is too loud, you should check whether the motor rotates poorly.
Look: Find the fault location and cause of the fault through observation. For example, when inspecting a household appliance that is not powered on, first check whether the fuse is blown to determine whether the load has overcurrent; when inspecting a washing machine motor that does not rotate, check whether the appearance of the motor and capacitor has changed color to determine whether they are normal.
Touch: Note that when using the touch method, you must ensure safety to avoid electric shock or burns. Find the fault location and cause of the fault by touching it with your hands. For example, when inspecting, you can judge whether the work is normal by touching the surface temperature of the motor, heater, and other components; when inspecting the washing machine washing motor that is not running smoothly, you can turn the impeller to see if it can rotate normally to determine whether there is any debris under the impeller.
Smell: Find the fault location and cause of the fault by smelling. For example, when inspecting the washing machine motor that does not rotate, if you smell an abnormal odor, it means that the motor or the running capacitor is damaged.
3. Voltage measurement method
The voltage measurement method is one of the most commonly used inspection methods. The fault location and cause of the fault are determined by measuring whether the AC voltage or DC voltage at the suspected point is normal. For example, when repairing a small appliance such as an electric kettle or an electric iron that is not working, you can measure whether the mains socket has a 220V mains voltage to confirm whether the mains power supply system is abnormal or the small appliance is faulty.
4. Resistance measurement method
The resistance measurement method is one of the main repair methods. By measuring whether the resistance of the suspected circuit and device is normal, the fault location and cause of the fault can be determined. For example, when repairing a blown fuse of an electric fan or washing machine, you can measure the resistance of the motor and running capacitor to determine whether they are normal; when repairing a rice cooker or electric frying pan that does not heat, you can measure the resistance of the heating plate to confirm whether it is open circuit. When measuring components using the resistance measurement method, it must be done with the power off, otherwise the multimeter is easily damaged.
5. Other methods
Current test method: Determine the fault by measuring whether the DC in the circuit is normal. If you suspect that the current in a circuit is too large, you can use the current test method.
Signal injection method: Inject the signal into certain circuits of the electronic product to be repaired, and observe the reaction after the signal is injected to determine the fault. The injected signal should match the circuit.
Substitution method: Replace the difficult-to-judge components with normal components of the same specifications to determine whether they are normal. When repairing small household appliance circuits, the substitution method is mainly used to determine whether capacitors, voltage regulators, integrated circuits, etc. are normal.
Isolation and segmentation method: Disconnect the suspicious part from the whole machine circuit or unit circuit to observe its impact on the fault phenomenon. This method is also called the open circuit method or segment search method.
Whole machine comparison method: Compare the electronic product to be repaired with the same type of intact electronic products, compare the circuit's working voltage, waveform, working current, etc., to find the fault location. This method is suitable for repairing electronic products that lack normal working voltage data waveform parameters and other maintenance information.
Temperature method: By touching the surface of some components, determine whether their temperature is too high, so as to determine the cause and location of the fault. This method is more useful when judging whether the power tube and rectifier stack of the induction cooker are working normally.
Cleaning method: For household appliances that are easy to enter water or are contaminated by oil smoke, such as small appliances in the kitchen and bathroom, the cleaning method can be used for maintenance. It is best to use anhydrous alcohol for cleaning, and then dry it in the air or a dryer before powering on the machine for testing.
When repairing electronic appliances, maintenance personnel should choose appropriate repair methods according to actual conditions and follow safe operating procedures to ensure the safety and effectiveness of the repair process. At the same time, maintenance personnel should also continue to learn new technologies and methods to improve their maintenance level.
1. Inquiry inspection method
This is the most basic method for repairing household appliances. Before repair, the maintenance personnel need to carefully ask the user about the fault characteristics and causes of the fault. For example, when repairing a remote control failure, if the remote control has been dropped, the circuit board should be checked for component pin desoldering; if not, the crystal oscillator should be checked. This method helps maintenance personnel quickly locate the problem and avoid unnecessary disassembly and misjudgment.
2. Visual inspection method
The visual inspection method is also a common method for repairing household appliances. During maintenance, this method can be used to make a preliminary judgment on the fault location. This method mainly judges the fault location through listening, looking, touching, and smelling.
Listen: Use your ears to find the fault location and cause of the fault. For example, when repairing small appliances such as color TVs and microwave ovens, if you hear a "pop" discharge sound, you should check whether the high-voltage device is discharged to the ground; when repairing electric fans and range hoods, if the mechanical noise is too loud, you should check whether the motor rotates poorly.
Look: Find the fault location and cause of the fault through observation. For example, when inspecting a household appliance that is not powered on, first check whether the fuse is blown to determine whether the load has overcurrent; when inspecting a washing machine motor that does not rotate, check whether the appearance of the motor and capacitor has changed color to determine whether they are normal.
Touch: Note that when using the touch method, you must ensure safety to avoid electric shock or burns. Find the fault location and cause of the fault by touching it with your hands. For example, when inspecting, you can judge whether the work is normal by touching the surface temperature of the motor, heater, and other components; when inspecting the washing machine washing motor that is not running smoothly, you can turn the impeller to see if it can rotate normally to determine whether there is any debris under the impeller.
Smell: Find the fault location and cause of the fault by smelling. For example, when inspecting the washing machine motor that does not rotate, if you smell an abnormal odor, it means that the motor or the running capacitor is damaged.
3. Voltage measurement method
The voltage measurement method is one of the most commonly used inspection methods. The fault location and cause of the fault are determined by measuring whether the AC voltage or DC voltage at the suspected point is normal. For example, when repairing a small appliance such as an electric kettle or an electric iron that is not working, you can measure whether the mains socket has a 220V mains voltage to confirm whether the mains power supply system is abnormal or the small appliance is faulty.
4. Resistance measurement method
The resistance measurement method is one of the main repair methods. By measuring whether the resistance of the suspected circuit and device is normal, the fault location and cause of the fault can be determined. For example, when repairing a blown fuse of an electric fan or washing machine, you can measure the resistance of the motor and running capacitor to determine whether they are normal; when repairing a rice cooker or electric frying pan that does not heat, you can measure the resistance of the heating plate to confirm whether it is open circuit. When measuring components using the resistance measurement method, it must be done with the power off, otherwise the multimeter is easily damaged.
5. Other methods
Current test method: Determine the fault by measuring whether the DC in the circuit is normal. If you suspect that the current in a circuit is too large, you can use the current test method.
Signal injection method: Inject the signal into certain circuits of the electronic product to be repaired, and observe the reaction after the signal is injected to determine the fault. The injected signal should match the circuit.
Substitution method: Replace the difficult-to-judge components with normal components of the same specifications to determine whether they are normal. When repairing small household appliance circuits, the substitution method is mainly used to determine whether capacitors, voltage regulators, integrated circuits, etc. are normal.
Isolation and segmentation method: Disconnect the suspicious part from the whole machine circuit or unit circuit to observe its impact on the fault phenomenon. This method is also called the open circuit method or segment search method.
Whole machine comparison method: Compare the electronic product to be repaired with the same type of intact electronic products, compare the circuit's working voltage, waveform, working current, etc., to find the fault location. This method is suitable for repairing electronic products that lack normal working voltage data waveform parameters and other maintenance information.
Temperature method: By touching the surface of some components, determine whether their temperature is too high, so as to determine the cause and location of the fault. This method is more useful when judging whether the power tube and rectifier stack of the induction cooker are working normally.
Cleaning method: For household appliances that are easy to enter water or are contaminated by oil smoke, such as small appliances in the kitchen and bathroom, the cleaning method can be used for maintenance. It is best to use anhydrous alcohol for cleaning, and then dry it in the air or a dryer before powering on the machine for testing.
When repairing electronic appliances, maintenance personnel should choose appropriate repair methods according to actual conditions and follow safe operating procedures to ensure the safety and effectiveness of the repair process. At the same time, maintenance personnel should also continue to learn new technologies and methods to improve their maintenance level.