How to use a digital multimeter to check the point of failure of the line
1. Appearance check.
You can touch the battery, resistor, transistor, integrated block temperature rise is too high. If the newly loaded battery is hot, it means that the circuit may be short-circuited. In addition, it should also observe whether the circuit is broken, desoldering, mechanical damage and so on.
2, waveform analysis.
With an electronic oscilloscope to observe the circuit voltage waveform, amplitude, period (frequency) and so on.
For example, such as measuring whether the clock oscillator vibration, if the oscillator has no output, indicating that the internal inverter is damaged, it may also be an external component open circuit.
3, measuring component parameters.
Components within the scope of the fault, online measurement or offline measurement, parameter values should be analysed. For resistance online measurement, should consider the impact of the components connected in parallel with it.
4, hidden fault elimination.
Hidden fault refers to the fault is hidden, the instrument is sometimes good and sometimes bad fault. Such failures are more complex, common causes include solder joints, loose, loose connectors, poor contact with the transfer switch, component performance is unstable, the lead will be broken and so on. In addition, also includes some external factors caused by. Such as high ambient temperature, excessive humidity or intermittent strong interference signals nearby and so on.
5, detect the working voltage at all levels.
Detect the working voltage at each point, and compare it with the normal value.
First of all, the accuracy of the reference voltage should be ensured, it is best to use a piece of the same model or similar digital multimeter for measurement and comparison.
