Multimeter maintenance and repair
Multimeter maintenance
1. Do not connect higher than 1000V DC voltage or higher than 700V AC RMS voltage. ,
2. Do not connect the voltage source when the function switch is in the Q and position.
3. Please do not use this watch when the battery is not installed or the back cover is not tightened.
Multimeter Repair
1. Visual inspection
If it is found such as disconnection, desoldering, short circuit, broken fuse tube, burned out components, etc., you can touch the temperature rise of the battery, resistor, transistor, and integrated block. You can refer to the circuit diagram to find out the reason for the abnormal temperature rise.
2 voltage measurement method
Measuring whether the working voltage of each key point is normal can quickly find out the fault point. Such as measuring the working voltage and reference voltage of the A/D converter.
3. Short circuit method
The method of checking the A/D converter generally adopts the short-circuit method, which is often used in the repair of weak and micro-electric 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 the situation where there is a short circuit in the circuit.
5. Measuring element 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.
