Invasive Electronic Sphygmomanometer Circuit Board Recovery needs to inspect the flip-flop trigger, strobes, register status, as well as the detection over discrete components and other components;
The status of IC devices such as flip-flops, registers, and strobes is often closely related to the status of other devices on the PCB board. Therefore, it is best to check these devices after confirming that there are no problems with other circuits. Common triggers and registers are 74374, 74174, 74173, 74164, 7474, 74122, etc.
When testing such IC devices of mainboard with an online tester, the online influence is sometimes greater, and the necessary analysis of the test waveform is also required.
Inspection of discrete components and other components
Various methods can be used to inspect transistors, resistors, capacitors, optocouplers, relays, switches, AD devices, analog ICs, and virtual soldering. VI curve testing, three-terminal device testing, programming voltage output, Functions such as integrated op amp testing, high-voltage interface testing, or other testing methods such as multimeters and oscilloscopes can be implemented directly.
After testing the main components of the faulty controller circuit card, if no fault has been found, the inspection of such devices is sometimes very important. Don’t omit or ignore some faults that we may not imagine.
Use the VI curve function to check devices not stored in the test library
When using an online tester to rework controller circuit boards, you often encounter devices that are not in the test library, especially some IC devices with complex functions.
Using VI curves to test these devices is not only simple and effective, but also effective. The test usually requires a reference board that is exactly the same as the well functional circuit board under test. If you have experience, you can also directly observe and analysis the VI curve between the device pins without the need to compare the same plate or sample to determine the device failure.
