PC Material Direct Plug-in 18W 24W DC Adapter

One, notebook computer power adapter without voltage output maintenance example

A notebook computer, in use, because of the power supply line problems so that the voltage rose suddenly, resulting in a power adapter burned out, no voltage output.

Maintenance process: The power adapter uses a switching power supply. The input voltage ranges from 100 to 240V. The voltage exceeding 240V May burn out the power adapter. Open the plastic case of the power adapter and see that the fuse has blown, the varistor has burned out, and one of the pins has burned out. Use a multimeter to measure the power supply circuit without obvious short-circuit phenomenon. Replace the fuse and varistor with the same specifications, and connect the power supply adapter. The power supply adapter can still run normally. In this way, the protective power circuit in the power adapter is relatively perfect.

From the actual circuit analysis, the varistor and the bridge rectifier diode input parallel, its function is: in the moment of high voltage invasion, using its "own fuse", thus protecting the power adapter part of the other components from high voltage damage.

Under the condition of normal 220V power supply voltage, if there is no varistor of similar specifications on the hand, emergency use can also temporarily not install the resistance.

But the varistor should be installed immediately after purchase, otherwise the future is endless, light will burn out many components in the power adapter, serious will burn out the laptop.

To repair the removed plastic shell of the power adapter, you can use polyurethane adhesive to patch. If there is no polyurethane adhesive, you can also use black electrical tape to wrap several circles around the plastic shell of the power adapter.