Laptop Model: Asus FX 60V
(1) The issue started with battery not charging with mains on. plugging and unplugging mains cord from laptop used to sometime resume charging. Finally, even plugging and unplugging did not start the charging
(2) Initially thought that the problem might be with the charging arrangement inside the laptop as the charger was giving proper 19 v output.
(3) opened the laptop and removed the battery. switched on the laptop, laptop used to get on for a second and then turn off and then restart again, google revealed that it was normal behaviour of asus laptop if battery not present. It was also found that the batt led was steady amber(condition when battery fully charged) even without battery present
(4) continued with this behaviour for few weeks, until I found that if power was also not switched off, after shutdown and then subsequent power-up, this "switch on once, then shutdown, then switch on" behaviour did not occur
(5) A new problem started after a few weeks, the laptop would shutdown automatically while working after a few minutes. opened and tested bios battery this time, found that bios battery was 0.7 volts.ordered new bios battery and fixed it somehow using tape. the original battery was rivetted to a wire using metal plates and 2 pin header at other end connecting to motherboard. even after changing the bios battery, this auto shutdown issue persisted.
(6) this time re-inserted the main laptop battery, and found not charging. switched off the laptop, here i made a mistake, should have removed the battery, but forgot. next morning , I found the battery voltage totally drained close to 0 v. so either some battery circuit inside has gone faulty discharging the battery or battery itself has grown dendrites and became faulty, either way I wouldn't know. That is the end of my laptop battery and not planning to replace it because of expenses.
(6) searched and got to this video..https://www.youtube.com/watch?v=mKNmYp3h2N8&lc=Ugzp8-mCVC9_pfVhUXN4AaABAg.9a48O7-4ZXd9a48ic7v7mE
where many in comments were saying that this issue (auto shut down) happens due to faulty keyboard. so This time decided to open everything, heatsink, fans, flat ribbon cable to keyboard, LEDs, touchpad etc. initially suspected that some clogging might be there in heaksink and thereby due to thermal issue, auto shutdown was happening. however, the heatsink was not much clogged, cleaned it nevertheless. cleaned the motherboard backside as seen in pic, little bit of dust was there.
(7) reconnected everything back and switched on, now the repeated switch on/switch off problem was not there and laptop straight away booted and did not shutdown after a pre-determined time, the battery led also blinks amber as it is supposed to do (trying to charge a non-existing battery) and is running ok ever since.
(8) Possible reasons for solving problem:-
(a) dust removed from the backside of the motherboard.
(b) keyboard connector removed and turned on resetting the chipset circuitary. later when keyboard connected as explained in step (6) and turned on, everything was fine.
(C) battery was anyway failing, that is why charging circuit was not charging. may be due to dendrites, it might be overdrawing current thus charging circuit was shutting the charge circuit.
Misc:
Some zoomed in view of MOSFETS (NCE 4688) which I had tested, and apparently had no issues
