Dell laptop charger light comes on for a sec and turns off?

[irepair559]

Hello guys i have a dell laptop , a newer one but doesnt power on.

When i plug in the charger i get a white light for a sec then 2 fast blinks


I did notice it was getting 19v on drain but not on other side nor on gate..

I did notice many mosfets Source's are measuring 1 ohm to ground and some around 70ohms, idk if thats normal?

what would be the next step?

Ps i see no water damage or anything unordinary , board looks new.

[kalilinux25]

Re: Dell laptop charger light comes on for a sec and turns off?

Hello guys i have a dell laptop , a newer one but doesnt power on.

When i plug in the charger i get a white light for a sec then 2 fast blinks


I did notice it was getting 19v on drain but not on other side nor on gate..

I did notice many mosfets Source's are measuring 1 ohm to ground and some around 70ohms, idk if thats normal?

what would be the next step?

Ps i see no water damage or anything unordinary , board looks new.

https://www.badcaps.net/forum/showthread.php?t=112584

post #3 schematic

[kalilinux25]

Re: Dell laptop charger light comes on for a sec and turns off?

Test the first and scecond mosfet

first mosfet is PQB11 check if voltage passes to the other side on pin 1,2,3 ,
If
19v is not [present, power off , ohms mode test pin 5 to 1 resistance and pin 5 to 4

same process to the secnd mosfet also

[irepair559]

Re: Dell laptop charger light comes on for a sec and turns off?

which would be the first mosfet ? Left or right one?

[mon2]

Re: Dell laptop charger light comes on for a sec and turns off?

PQB11.

See attached.

[irepair559]

Re: Dell laptop charger light comes on for a sec and turns off?

PQB11.

See attached.

how can that be the first mosfet ? its a ways down from the dc jack ? i thought it would be those i pictured near the dc jack

[irepair559]

Re: Dell laptop charger light comes on for a sec and turns off?

Test the first and scecond mosfet

first mosfet is PQB11 check if voltage passes to the other side on pin 1,2,3 ,
If
19v is not [present, power off , ohms mode test pin 5 to 1 resistance and pin 5 to 4

same process to the secnd mosfet also

im getting 19v

[Sephir0th]

Re: Dell laptop charger light comes on for a sec and turns off?

Next step could be to look which power rails are coming up as soon as you plug the charger and if you loose some voltages when the white light disappears.
The big grey coils all over the board would be good points to check for voltages.

[irepair559]

Re: Dell laptop charger light comes on for a sec and turns off?

i get 19v here at these mosfets drains but not on other side

[Sephir0th]

Re: Dell laptop charger light comes on for a sec and turns off?

Well, if you don't follow the advise you likely won't make any progress here.
These two phases are very likely related to the VRM circuit, probably +VCC_CORE, which comes up in the late sequence.

[irepair559]

Re: Dell laptop charger light comes on for a sec and turns off?

Well, if you don't follow the advise you likely won't make any progress here.
These two phases are very likely related to the VRM circuit, probably +VCC_CORE, which comes up in the late sequence.

i thought i did what you asked? sorry so u want me to measure what points "loose" power as soon as the light is off? thats only half a second or so thatll be hard. Ill probe around coils to see what readings i can get. Thanks