How many types are there approximately for the methods of troubleshooting Fluke multimeters?
A multimeter can not only be used to measure the resistance of the object being measured, alternating and direct current voltages, but also direct current voltages. Moreover, some multi-meters can even measure the main parameters of transistors and the capacitance of capacitors, etc. Mastering the usage method of a multimeter proficiently is one of the most basic skills in electronic technology. Common multimeters include analog multimeters and digital multimeters. An analog multimeter is a multi-functional measuring instrument with a meter head as the core component, and the measured values are read by the indication of the meter head pointer. The measured values of a digital multimeter are directly displayed in digital form on the liquid crystal display screen, which is convenient to read, and some even have a voice prompt function. A multi-meter shares a single meter head and integrates a voltmeter, an ammeter, and an ohmmeter into one instrument.
The occurrence of faults in multimeters is due to multiple factors, and the problems encountered are highly random with not many rules to follow, making the repair work quite difficult. The editor below has sorted out some repair experiences accumulated in years of practical work for your reference. The methods for troubleshooting Fluke multimeters can be roughly divided into the following types:
(1) Voltage measurement method: Measuring whether the operating voltages at each key point are normal can quickly identify the fault location. For example, measure the operating voltage and reference voltage of the A/D converter, etc.
(2) Sensation method: Rely on the senses to directly make a judgment on the cause of the fault. Through visual inspection, problems such as broken wires, unsoldered joints, short circuits due to wire crossing, blown fuse tubes, burned-out components, mechanical damage, raised and broken copper foils on the printed circuit board can be found. You can feel the temperature rise of batteries, resistors, transistors, and integrated circuits, and refer to the circuit diagram to find the cause of abnormal temperature rise. In addition, you can also check with your hand whether the components are loose, whether the pins of the integrated circuit are firmly inserted, and whether the transfer switch is jammed. You can hear and smell any abnormal sounds or odors.
(3) Open-circuit method: Disconnect the suspicious part from the entire machine or the unit circuit. If the fault disappears, it indicates that the fault lies in the disconnected circuit. This method is mainly suitable for situations where there is a short circuit in the circuit.
(4) Short-circuit method: In the methods of checking the A/D converter mentioned above, the short-circuit method is generally adopted. This method is frequently used when repairing weak current and microelectronic instruments.
(5) Component measurement method: When the fault has been narrowed down to a certain location or several components, in-circuit or out-of-circuit measurement can be carried out on them. If necessary, replace the components with good ones. If the fault disappears, it means that the component is damaged.
(6) Interference method: Use the human body induction voltage as an interference signal and observe the change of the liquid crystal display. This method is often used to check whether the input circuit and the display part are in good condition.
