How to troubleshoot the multimeter can be roughly divided into several types?
The multimeter can be used not only to measure the resistance of the object to be measured, but also to measure the AC and DC voltages as well as the DC voltage. Even some multimeters can measure the main parameters of transistors and the capacitance of capacitors. It is one of the most basic skills of electronic technology to be fully proficient in the use of multimeters. Common multimeters include pointer multimeters and digital multimeters. The pointer multimeter is a multi-functional measuring instrument with the meter head as the core component, and the measured value is read by the pointer of the meter head. The measured value of the digital multimeter is directly displayed in digital form by the liquid crystal display, which is easy to read, and some also have a voice prompt function. A multimeter is a meter with a common head, which integrates a voltmeter, an ammeter and an ohmmeter. There are many factors in the failure of the multimeter, and the randomness of the problems encountered is large, there are not many rules to follow, and it is difficult to repair. The front editor sorts out some repair experience accumulated in many years of actual work for your reference. The troubleshooting methods of the Fluke multimeter can be roughly divided into the following categories:
(1) The voltage measurement method measures whether the working voltage of each key point is normal, and can quickly find out the fault point. Such as measuring the working voltage and reference voltage of the A/D converter.
(2) The sensory method directly judges the cause of the failure by means of the senses. Through visual inspection, it can be found such as disconnection, desoldering, short circuit, broken fuse tube, burnt out components, mechanical damage, and copper foil on the printed circuit. Lifting and breaking, etc.; you can touch the temperature rise of batteries, resistors, transistors, and integrated blocks, and you can refer to the circuit diagram to find out the cause of abnormal temperature rise. In addition, by hand, you can also check whether the components are loose, whether the integrated circuit pins are firmly inserted, and whether the transfer switch is stuck; you can hear and smell whether there are abnormal sounds and odors.
(3) The disconnection method disconnects the suspicious part from the whole machine or unit circuit. If the fault disappears, it means that the fault is in the disconnected circuit. This method is mainly suitable for the situation where there is a short circuit in the circuit.
(4) Short-circuit method In the A/D converter inspection method mentioned above, the short-circuit method is generally used. This method is often used when repairing weak and micro-electric instruments.
(5) Measuring component method When the fault has been reduced to a certain place or several components, it can be measured online or offline. If necessary, replace it with a good one. If the fault disappears, the component is broken.
(6) The interference method uses the human body induced voltage as an interference signal to observe the changes of the liquid crystal display. It is often used to check whether the input circuit and the display part are intact.
