As a sensitive optical device, SFP module often have many problems during use. For the more common problems of optical modules, there are corresponding test methods, such as visual inspection to see the appearance, comparison method to measure parameters to see the difference, replacement method Replace the components to see the parameter changes, and determine the fault according to a certain bad condition.
- Visual inspection to see the appearance
Look at the appearance of the optical module by visual inspection, check whether there are obvious signs of damage on the surface of the module, and then check whether the components are cracked, leaking, tin or even blackened.
- Compare the measured parameters to see the difference
If there is any problem with the visual method, you can use the relevant testing instruments to detect the same new module and the module that may be faulty, and divide it into two cases: energized and non-energized, and check the circuit parts or components. Parameters such as voltage, resistance value and waveform, and then comparing the test results of the new module and the bad module can determine the problem.
- Replacement method Replace components to see parameter changes
If there are differences in the description of the test parameters, you can replace the corresponding components or components of the module that may be faulty with good components or components of the same model, and test the parameters again to see if they return to normal.
- Determine the faulty circuit area according to a certain bad condition
Determine the faulty circuit area according to a certain bad condition, such as: poor optical power mainly check the transmitting area, poor sensitivity check the receiving area, etc., which can reduce maintenance time and improve efficiency.
- Determine the components of the fault through the structure of the hanging optical module
We all know that the optical module is mainly composed of TOSA components, ROSA components and PCBA board. If you want to judge the faulty components, there are several ways to judge:
(1) Remove the TOSA components and ROSA components, and then test their performance on the component test board.
(2) In the case of power-on, use a multimeter to measure the voltage of each pin to see if the voltage value is normal; in the case of power-off, use a multimeter to test whether the circuit led by the pin and the pin is connected.
(3) According to the bad condition, test the corresponding parameters to see the change of the parameters. For example, if the bad reason is “low optical power”, then you can test the power of the module. If you increase the power, the reading of the power meter will increase, and the bias will increase. The current BIAS value also increases with the increase of the working current. This change shows that the PCBA circuit is turned on, and the drive performance and storage performance are no problem. From this, it can be preliminarily judged that the TOSA optical power is poor and the PCBA board is good, but it does not rule out the possibility of poor PCBA.