phone automatically switch off

@robinsingh45676 First check your charger. Make sure it has proper output. Then check your charging cable. Check to make sure connectors are not bend etc. After that, check the charging port. Clean it of any debris etc, use a few puffs of air to clean it out. If none of this works, get a USB ammeter and see if your phone draws any amperage from the charger. If it does not it is possible that this is a charging port issue or a bad battery.

To check the charging port, use a voltmeter and measure the voltage on your battery connector. Next plug your phone charger in. Now measure the voltage on your battery connector. That voltage will have to have increased. IF not then the issue is either the port or the charging circuit.

The A series has issues with the flex cables coming from the charging board to the main board. CHeck that for micro tears and corrosion and proper connection to the boards. I suggest that you start with a new battery if any of the above did not work. After that it's the charging board and flex cables.

You can also go ahead and use the Samsung flowchart

The parts to check are within the blue rectangle