Clever judgment on semiconductor diode circuits

Semiconductor diodes are widely used in electrical circuits. Once the original diode is damaged, it must be replaced with a new one. The quality of the pipe to be replaced can be judged as shown in the figure. In the figure, T is the 220/3V-2W power transformer, VD1 and VD2 are 2CP10 rectifier diodes, H1 and H2 are light-emitting diodes, and VDX is the diode to be tested. During the test, insert VDX into sockets X1 and If it does not light up, it indicates that the diode under test is open circuit internally.