Methods for Troubleshooting and Repairing Multimeters
1. By relying on sensory perception, one can make decisive decisions on the causes of obstacles, such as wire breakage, desoldering, short circuiting of wires, fuse tube breakage, burning of components, mechanical damage, copper foil warping and breakage on printed circuits, etc., through surface inspection; You can touch the temperature rise environment of the battery, resistor, transistor, and integrated block, and refer to the circuit diagram to find the cause of the temperature rise. In addition, you can also check by hand whether the components are loose, whether the integrated circuit pins are firmly inserted, and whether the conversion switch is stuck; You can hear and smell any unusual sounds or odors.
2. The voltage measurement method is used to check whether the voltage at each critical point is normal, which can quickly identify any obstacles. Measure the operating voltage, reference voltage, etc. of the A/D converter.
3. The short-circuit method is usually accepted in the essentials of checking A/D converters mentioned earlier, and this method is commonly used when repairing weak and micro electrical instruments.
4. The circuit breaking method stops the suspicious department from disconnecting from the entire machine or unit circuit. If the obstruction dissipates, it manifests as obstruction in the disconnected circuit. This method is important in environments where there is a short circuit in the circuit.
When the obstruction has been reduced to a certain or several components, it can be measured online or offline using the component measurement method. When necessary, replace the components with good ones. If it hinders dissipation, indicate that the components are broken.
6. The disturbance method uses human perceived voltage as a disturbance signal to inspect the changing environment of LCD performance, and is commonly used to check whether the input circuit and performance department are complete.
