Dell mini 10
PCB : - LA-5091P
Problem Reported : - not power on with adaptor , not charging , display ok with battery
Observation :
Laptop was working fine in battery mode but not able to charge the battery even not powering on with adaptor
Earlier engineer already changed charging ic mosfets and all
Actual Fault :-
So step by step checking for requirement found ACIN missing on IO controller
Checking for sources in schematic for. ACIN , found that a comparator LM393 is used for this requirement
Pin1 has 0 volts ( no output)
Checking through the inverting terminal and non inverting terminal of the op amp found low voltage at pin3 checking through the input line found PR3 value went high to 180k
Whereas it should be 82.5K , So replaced the resistor and Bingo
ACIN was available and
Job done
Conclusion :- Missing IO requirement ACIN
