820-3115-B Short ot GND

[Myrthos]

Good Morning dear colleagues,

I have a board with a bad short to gnd on pp18v5_conn after the fuse.

I have pp3v42 rail when battery is connected, but before clearing the short i don't believe i will have PPDCIN_S5_CHGR from the charger. U7000 is good and D7005 is good.Which indicates short might be internal??

No visible water damage on the board. Laptop is working perfectly on battery power so i assume CPU, GPU Keyboard are Ok.

Anyone had a similar issue please advise?
Thank you in advance.

[dellxps15]

Re: 820-3115-B Short ot GND

u need lab psu.

[keeney123]

Re: 820-3115-B Short ot GND

pp18v5 I do not have schematic for this. I would think the short is on a component, if the board had been working. It might be possible to twist the board enough to cause an internal board short. Many people detect component shorts with a external power supply an feel if any component is getting hot.

[bushie]

Re: 820-3115-B Short ot GND

Hello i have a short too around the battery connecter i cant trace it, here is a schematic it might help you, i would appreciate if you post any of your conclusions.

[dellxps15]

Re: 820-3115-B Short ot GND

Good Morning dear colleagues,

I have a board with a bad short to gnd on pp18v5_conn after the fuse.

I have pp3v42 rail when battery is connected, but before clearing the short i don't believe i will have PPDCIN_S5_CHGR from the charger. U7000 is good and D7005 is good.Which indicates short might be internal??

No visible water damage on the board. Laptop is working perfectly on battery power so i assume CPU, GPU Keyboard are Ok.

Anyone had a similar issue please advise?
Thank you in advance.

short could be one mosfet that generate 12.5 volt. they are 2. i have changed many of them to solve short on that 18.5 volt lane. also u7000 was bad each time in my case.

[bushie]

Re: 820-3115-B Short ot GND

https://drive.google.com/drive/folde...HcwR05EbUJfREk

[Myrthos]

Re: 820-3115-B Short ot GND

Thank you all for the replies.

Tonight all will be solved.

I have measured the mosfets and they are good.

Two possibilities left :

1. Internal board short.
2. Q5490 to have internally shorted that's a complimentary p channel n channel fet

I will write more tonight.

Cheerio

[Myrthos]

Re: 820-3115-B Short ot GND

Sry by mosfet i meant the two inrush limitting ones feeding u7000

[dellxps15]

Re: 820-3115-B Short ot GND

i mean q7030 q7035. u measured them right ?

check also q7080 q7085

1° remove q7085 and see if still short and wich side.... if pin 1-2-3 or pin 5-6-7-8 then remove q7080... anche check pins

then check q7030 q7035 or u7000