How to Repair a Multimeter
1. Appearance inspection: If it is found that such as disconnection, desoldering, short circuit, broken fuse, burnt component, etc., you can touch the temperature rise of the battery, resistor, transistor, and integrated block, and you can refer to the circuit diagram to find out the temperature. The reason for the abnormal rise.
2. Voltage measurement method: measure whether the working voltage of each key point is normal, which can quickly find out the fault point. Such as measuring the working voltage of the A/D converter, the reference voltage, etc.
3. Short-circuit method: The short-circuit method is generally used in the method of checking A/D converters, and this method is used more when repairing weak and micro-electrical instruments.
4. Circuit breaking method: Disconnect 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 short circuits in the circuit.
5. Measured component method: When the fault has been reduced to a certain place or a few components, it can be measured online or offline. If necessary, replace with good components. If the fault disappears, the components are broken.
