hi guys
my tester died today
all components are scratched
i know its probebly irreparable but i like to know how it works
this is what i find on pcb

area 1 is for charging test battery , mosfets were damaged before and it works again after replace them
area 2 is for charging backup battery, this area also had problem before and i remove mosfets and tester works after remove
area 3 is where we have problem now,controller is is warming
i have no idea what this area do
and this is how mosfests connect as i found

the picture is not good enough, I think the bottom integrated worked at high temperatures until it failed. The pcb around it is too colorful. Find the data sheet for that component. maybe it helps you