The reason of the  power module short-circuited as following:

1. The power module interface is improperly connected. It maybe caused by the loose plug, or the connector fall off or loose.
2. The component failure within the power module: The component failure within the power module, such as the capacitor and transformer damage, caused the output current of the power module is too large, resulting in a short circuit. In this case, you need to replace the faulty component and repair the power module.
3. Over input voltage: If the input voltage exceeds the rated voltage range of the power module, It will also cause a short circuit in the input. In this case, you need to adjust the input voltage or use a suitable device to limit the input voltage.
4. Module damage: If the power module is damaged, such as poor contact of electronic components, poor welding and other reasons, It will also cause the short circuit at the end of input. In this case, you need to replace the power module.