When the circuit of the display is faulty, its corresponding circuit part will inevitably occurs, and always react in the resistance, voltage, and current. It is characterized by flexibility. It can be examined one by one to suspicious bad members. The following is described.
Resistance detection
That is to use the resistance of some suspicious components, suspicious points, and integrated circuits in the electrical resistance unit. For the measured value to the measured value, the component can be quickly concluded whether the component is damaged, deteriorated, whether there is an open circuit and short circuit, whether there is a transistor to be broken. This method is the most effective effect on repairing open or short-circuit faults and determining fault components.
In order to ensure the safety reliability of the overhaul, the filter capacitor is discharged to the filter capacitor before performing resistance measurement, and the large capacitor storage is prevented from being burn a meter. The resistance detection is generally combined with "forward resistance test" and "reverse resistance test". "Reverse resistance" is the result of using a black table pen and uses the red table pen measure. The "forward resistance" is the result of using a red table brush and uses a black table pen measure.
The online resistance measurement method and the debris resistance measurement method are often used during the maintenance process. On the line resistance measuring method, the resistance of the component is measured on the circuit board. Since the measurement element is connected to the board, the measured value is subject to other strings, the parallel branch, so the measurement results should be considered. The debris resistance measurement method is often used during the maintenance process, and its method is simple and fast. It is a method of delising one end or the entire element of the component to the entire component, and then performing a method of resistance measurement. In order to reduce the measurement error, the measurement is measured when the meter should use the appropriate gear. For some of the resistances of some key parts, it is necessary to use positive and reverse table written measurements to improve the accuracy of judging the fault.
In summary, when using an online resistance measuring method, the appropriate measurement method should be selected according to the line, and should be randomly strained, and the debris resistance measurement method is obtained if necessary. Only two methods are used in conjunction, complement each other, to exert the advantages of the resistance inspection method, and obtain the correct result.
2. Voltage Measurement Method
The voltage detecting method is a method of determining a fault location or a faulty element with a multimeter by a working voltage of a circuit or a circuit in a circuit or a circuit in a circuit or a normal value. Generally, the voltage phase difference is obvious or a larger voltage fluctuation is a part of the fault.
Voltage measurement method, generally there are two kinds. One is a static voltage detection method, which is measured when the display does not input the signal. The other is a dynamic voltage measurement method, which is the voltage value measured when the display is connected to the signal.
Voltage detection is generally a voltage value for detecting a key point. Depending on the voltage of the key point, reduce the fault range and quickly find the faulty component. For example, a light-free display is generally used first, and the high-use measuring B voltage is high, or is low, it is zero, or normal. The corresponding diagnostic direction can be made according to the measured voltage value. The author has repaired a MF1766 color display. The fault phenomenon is no light. When the B voltage is measured, it is more than ten volts and the needle has a slight swing. The similar problem is either a power supply circuit itself, or the load is overweight, When the view voltage is detected, it should be 80V, and the surface is measured. It is suspected to be protected by the load short circuit. The 80V load is disengaged, the boot measurement, B is normal, 80V is normal, the determination is a load problem, quickly find Fault component. If B is a voltage of 0V, the fault phenomenon is on the indicator, and cannot be turned on. The author will open a 220v60W light bulb to a fake load, then the machine is normal, and quickly find the load circuit, and eliminate the fault directly. Then, if the B voltage is normal, first look at the circuit has no work, if the circuit is normal, then there is a light wire, and look.
