power ic or mobo dmg?

i have a note 2 canadian model sgh i317m. A few months back i found that my note 2 was getting very hot and slowing down ALOT when doing the mist mundane tasks.. then all of a sudden i saw the battery LED flashing multi colours ... it would change from blue to white to green to yellow..all colours of the rainbow. After a couple minutes, the phone would not start up again.

I went to buy original oem new samsung battery and replaced it.. it still would not start.. I also replaced the usb charging flex component. Still no luck.

After a few weeks, I read online that the problem could be the power IC unit The voltage is not being suffuciently chopped up and being delivered to all of the diff internal components. The label on the power ic unit is very small and half rubbed off.. but it looks like it says MAX77867 or something like that.

Is it possible the problem could be the power IC unit ? How can I test which internal component is at fault here? I have a multimeter with me. Any directions to move forward would help.

Thank you