When you repair the power supply part and repeatedly damage it after replacement, the switch tube as soon as the power is turned on. Don't worry, of course, the maintenance expert has experience, it is not a problem, but the long-term use of this tester can bring you high efficiency when repairing the power supply. Save working time! You should first test whether the switching former is short-circuited between turns. The test is very simple! Connect the inst ent to the 5v power supply, and the tester has been upgraded to use the USB interface of the 5v charger for Android phones, so this test The inst ent is not equipped with a power supply when it is sold. The customer should prepare it by himself. Please be aware that the two fish plagues are connected to the winding ends of the former coil with a large number of turns. Now! Because all the windings of the former are on the same pair of magnetic cores! So as long as there is a group of green lights, it proves that the whole former is not short-circuited! It is not necessary to test each group. Note, this tester can only test high-frequency with magnetic cores! It can also test step-up with magnetic cores, and can not test power frequency with steel sheets! It can also be tested online, (but the power board is not live! It can be reflected Check whether the output load of the former is normal or there is a short circuit, such as rectifier breakdown, output capacitor short circuit, etc. Finally, remove the former again and make sure again. If it is still short, you can carefully disassemble the former and use the same No. rewinding. High-voltage package can also be tested! Test 110v winding Note, this tester can only measure short-circuit between coils! Most high-voltage packages are short-circuited , but there are also poor insulation or high-voltage rectifier diode breakdown. This inst ent is insulated Faults and rectifier diode breakdown cannot be detected. Please be aware of this. The tester uses a normal former to test the strong state, artificially short-circuit the secondary of the former. If the indicator light changes, it proves that the tester is working properly! Colour:As Shown Material:plastic Package Contents: 1 x Switching Power Supply former(Due to different product batches, the product appearance and cable color , which not affect the use) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.