lenovo ideapad 3 14il05

[yaso143]

gs454/gs554/gv450/gv550 nm-d031

can anyone help ?
first issue short in main power rail fixed by replacing a mosfet

new issue

unit turns on after 5 seconds it turns off (when battery is plugged)
unit turns on then off immediately(when batt is unplugged and using charger only)

main power rails are present 20v , 3.3v is present 5v is present 1.8v is present when unit is turned on 1.8v shows then disappear when unit shuts itself down

also i noticed that cpu is getting hot then turns off do you have any suggestion what to look next

[Sephir0th]

Re: lenovo ideapad 3 14il05

You need to share the full history first. Which mosfet did you replace before? If it was related to a power supply for the CPU there is nothing to wonder about the behaviour. A dead CPU is a common outcome after a high-side short.

[yaso143]

Re: lenovo ideapad 3 14il05

heres the mosfet that i replace pq3403 yep iguess it was a dead cpu unfortunate

[yaso143]

Re: lenovo ideapad 3 14il05

You need to share the full history first. Which mosfet did you replace before? If it was related to a power supply for the CPU there is nothing to wonder about the behaviour. A dead CPU is a common outcome after a high-side short.

how can i identify if its a highside and lowside mosfet

[mcplslg123]

Re: lenovo ideapad 3 14il05

Yes its a high side mosfet as it receives VIN(19V) on drain pins(pin5-8) and cpu is killed as 19V has gone to cpu. So end of story unless you intend to replace the cpu.

[yaso143]

Re: lenovo ideapad 3 14il05

Yes its a high side mosfet as it receives VIN(19V) on drain pins(pin5-8) and cpu is killed as 19V has gone to cpu. So end of story unless you intend to replace the cpu.

yes its a goner replacing cpu's is not practical in my situation