Check that the charger ofinput plug is well connected to the power supply, you can plug the charger input plug into the normal power outlet to try. If the situation remains the same, open the charger shell, observe whether the fuse in the machine has broken, if not broken, first check whether the power input line is good.
After troubleshooting the input line of the power supply, we should check whether the components near the high voltage area on the circuit board have virtual welding, whether the fuse seat is in bad contact, and focus on checking the transformer T1 and the transistor v1. V2, etc. Whether there is a virtual welding phenomenon.
In addition, R5 or R6 open circuit, will also cause the above trouble, if the inside fuse has broken, do not replace the big amperes fuse tube (the charger fuse tube is generally 2 a). Emphasis should be placed on checking for damage to d1-d4v1v1v2nr7 and d15d21, if damaged, can be replaced by the same type.
Please note that when the above components are damaged, there will be one or two damage at the same time. Sometimes there may be several damage at the same time. When checking, it is necessary to check one after another. After changing these components, the electricity will be electrified.