1. Observation and inspection
Observation and inspection method refers to the method to check the faults by observing the appearance of the main board of the industrial tablet PC and whether the components are abnormal.
When overhauling the industrial motherboard, firstly, observe whether the capacitance on the industrial motherboard is bulging, leaking or seriously damaged; whether the resistance and capacitance pins collide, whether the surface of board is burnt, whether the chip surface is cracked; whether the copper foil is burnt.
Check whether the plugs and sockets are skewed; check whether there is any foreign matter falling into the components of the industrial main board; check whether the chip is abnormally hot.
2. Comparative method
The comparison method is a simple and easy maintenance method. When repairing, prepare the main board of the same model as the faulty industrial main board. When some modules are suspected, test the same test points of the two main boards respectively, and compare them with the faulty main board with the correct characteristics (waveform or voltage) to see which module's waveform or voltage is inconsistent, and then detect the inconsistent parts point by point until locate and resolve the problem.
3. Measurement method
The measurement methods include resistance measurement and voltage measurement.
Resistance measurement is a method of measuring resistance value to roughly judge the quality of industrial motherboard chip and electronic components, as well as the serious short circuit and open circuit of the circuit. For example, the diode is used to measure whether the transistor is seriously short circuited or open circuited, or the resistance of ISA slot to the ground is used to judge the quality of Southbridge chip.
The voltage measurement method is mainly to find out the different test points by measuring the voltage, and then compare with the test points of the normal industrial main board, and finally find out the faulty components along the line (running circuit) of the test points, and eliminate the faults.
4. Replacement method
The replacement method is to replace the suspected components with good components. If the fault disappears, it means that the doubt is correct. Otherwise, it is a judgment error, and further inspection and judgment should be made.
5. Temperature rise and fall method
The rising and falling temperature method is mainly aimed at the failure of the main board of the industrial tablet PC caused by the poor thermal stability of a certain component. When the temperature rise of the suspected components is abnormal and perceptible, use the cooling method to force them to cool down. If the fault disappears or tends to reduce, the thermal failure of the components can be judged. When the fault occurs after power on for a long time or the fault appears with the seasonal change, the suspected components are heated with the method of heating up to make them warm up. If the subsequent fault occurs, it can be determined that the thermal stability is poor.
6. Cleaning inspection method
The cleaning inspection method is applicable to the complex working environment of the industrial tablet PC, and it is suspected that the failure of the industrial main board may be caused by dust, etc. When cleaning, brush off the dust on the industrial main board with a brush. In addition, some cards and chips on the industrial motherboard are in the form of pins, which are often in poor contact due to pin oxidation. The oxide layer on the surface can be removed by the eraser and re-inserted.