How to eliminate the Glitch of digital multimeter
1. Waveform analysis
Use an electronic oscilloscope to observe the voltage waveform, amplitude, period (frequency), etc. of each key point in the circuit, such as measuring whether the clock oscillator is on and whether the oscillation frequency is 40kHz.
If the oscillator has no output, it indicates that the internal inverter of TSC7106 is damaged or the external component is open. The waveform of the {21} pin of TSC7106 should be a 50Hz square wave, otherwise it may be due to damage to the internal 200 frequency divider.
2. Measuring element parameters
For online or offline measurements of components within the fault range, parameter values need to be analyzed. When measuring resistance online, it is necessary to consider the influence of components in parallel with it.
3. Hidden troubleshooting
Implicit faults refer to faults that appear and disappear from time to time, and the instrument is sometimes good or bad. This type of fault is relatively complex, and the causes of the fault include solder joints being loose, loose connectors, poor contact of the transfer switch, unstable component performance, and continuous disconnection of the leads.
In addition, it also includes faults caused by external factors, such as high ambient temperature, high humidity, or intermittent strong interference signals in the vicinity.
4. Visual inspection
Check if the temperature rise of the battery, resistor, transistor, and integrated block is too high by touching them with your hand. If the newly installed battery heats up, it indicates a short circuit in the circuit. In addition, it is necessary to observe whether the circuit is disconnected, desoldered, mechanically damaged, etc.
5. Detect working voltage at all levels
Check the working voltage at each point and compare it with the normal value. Firstly, ensure the accuracy of the reference voltage. It is best to use a digital multimeter of the same model or similar for measurement and comparison.
