Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

[Blacktek]

hi guys merry Christmas!!!

I have a dell thats shorting out my charger, keeps blowing one mosfet specifically, everytime i replace it, it goes bad as soon as i plug it in.
the mosfet in question is PQ101. I removed the charger IC and the problem goes away, no shorted power adapter and no blown mosfet...could this be a bad charger iC? i just want to know your input before i order it.

[TossDon]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

There should be something short in that circuit, find that out first. By removing the IC you isolated the short. Check all the caps, specially on the B+ line.

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

There should be something short in that circuit, find that out first. By removing the IC you isolated the short. Check all the caps, specially on the B+ line.

thankx for the tip, ill check it out

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

There should be something short in that circuit, find that out first. By removing the IC you isolated the short. Check all the caps, specially on the B+ line.

Check all caps near IC and found no problems
Replaced Charger IC (isl88731) and problem still exist, shorting out pq101 and charger

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

heres the schematic

[the-sky-blue]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

hello friend ,
step 1 : disconnect PL100 then connect you charger
2: if the short circuit stay chick (PQ101 , PQ102 , PQ108 , PQ110) by using dmm (set dmm at buzzer mode ) if resistance was between (0.2-0.1 ) you must replace that mosfet (you must replace the same number )
3 :if the short circuit stay then remove PQ101 , connect your charger if it working you must change the charger ic ( ISL88731=BQ24745)

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

hello friend ,
step 1 : disconnect PL100 then connect you charger
2: if the short circuit stay chick (PQ101 , PQ102 , PQ108 , PQ110) by using dmm (set dmm at buzzer mode ) if resistance was between (0.2-0.1 ) you must replace that mosfet (you must replace the same number )
3 :if the short circuit stay then remove PQ101 , connect your charger if it working you must change the charger ic ( ISL88731=BQ24745)

thanks my friend but no luck, still same problem.
I removed the shorted pq101 and replaced it with a ao4407,then removed the pl100. reconnected to laptop but it shorted out pq101 for the 5th time..

[cyberhack]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

B+ check for short on the line must have short for PQ101 to short out get bench supply to aid with locating the short.

[cyberhack]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

ie page 50

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

B+ check for short on the line must have short for PQ101 to short out get bench supply to aid with locating the short.

thanks a lot for the input..I followed the B++ circuit, and found out that PIN 16(vin) on the charging IC (pu200) is shorted to ground but even when i remove the ic the problem still there.
Also all the components that show on pin 13 are missing, i think the @ symbol means it supposed to be missing.
Also i found out that PC1294 is shorted to ground, it popped(busted) while removing it, but the other side is connected to +VCCP!! now is this bad?

[the-sky-blue]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

do you have power supply
you can up current to max ,then look What be burn

[stj]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

have you tried without the battery?

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

do you have power supply
you can up current to max ,then look What be burn

Dont have power supply

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

have you tried without the battery?

I did, bare motherboard same issues

[Blacktek]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

do you have power supply
you can up current to max ,then look What be burn

getting a power supply soon

[itr]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

hey blactek did you manage to fix this. have something similar

[rs232killer]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

Hi
We use a flir cam to search "badcaps" or bad boys mosfets, its a bit expensive but they already have some cheap models for Apple and Android.

If you came across with one or someone that have one maybe save the day and motherboard.

For those that do this all day long ... buy one and stop having cap marks burned on the finger, i saved lots of time when its mosfets that barely heat and are the cause for the problem.

Regards
RS

[gcomputers]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

Hi i have similar problem B+ is shorted with ground , PQ101 burned (replaced it burned again ), VIN on PU100 is shorted with ground(replaced it the same short again ) , .

Any help please

[meritosari]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

-Pq100 & PQ101 (ac_fet), if one of them shorted then that indicate there's have problems with B+ (19v)or to much high current flow with it. a bit experience, also could be followed with other components has shorted.
could be bad caps, mosfets or ic chips.
-B+ spread to dc/dc 3.3v/5v, also to high side mosfet each dc/dc's, and reach to connector ldvs
-make sure before do replacement, the short circuit on B+ has gone, you can check resistance versus ground on the empty pad after you had removed components
-if want to inject with psu, not over than 1v . except you know there's no high side mosfets dc/dc has shorted. a little trick, if you want to increase voltage psu, while that do measure on coil cpu core, 1.05v (that has just low volatages). if you've find voltage on a coil, so high side mosfet has shorted.
-you see on schematic. 19v transform to other name vin>>>>p2>>>>>p3>>>>>B+>>>>>CHG_B+ and B++ to rt8205, whereas same 19v
-at last, check Batt+ not shorted to ground

[tibd]

Re: Dell inspiron 15 shorting out charger (la-9104p) keeps blowing mosfet

Had same problem once on one of boards, turned to be pc502 in the circuitry of pq500. then the problem returned after a week later, the issue then was at the same circuitry but this time pc501. Ended changing all those four caps, device never returned back to me, may be to someone else!!