OK....

Absent any external components showing a failed condition, your hot component may be bad internally. Double check the components connected to the pins. Look at that schematic in the pdf and the table below the pinouts.

What is the battery voltages ... on the wires you still have disconnected?

 

OK....



What is the battery voltages ... on the wires you still have disconnected?

It's 4.2 volt

 

OK....

Absent any external components showing a failed condition, your hot component may be bad internally.

I am not sure that I will be able to desolder these small IC myself. I will have to take some expert's help to desolder this IC from tha board.