Dell Inspiron LA-D801P Motherboard completely dead

[SMDFlea]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Put back everything in place.
As i said without jumper the shortcircuit is gone but still no voltage at PIN19.

Was the short gone on both sides

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

@dellxps15 removed pjp501,pjp801,jp5 and jp9 but shortcircuit is still there.
@SMDFlea no the one side is still with shortcircuit.

[SMDFlea]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Remove UZ3 next, check if the short is gone .

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

I prefer not to remove IC unless we have other option, reason is that they are without pins and it's hard to resolder them.
If we have no other option i will remove it.

[SMDFlea]

Re: Dell Inspiron LA-D801P Motherboard completely dead

After you removed all the jumpers the only thing i can see thats left to check is UZ3 . If you want to wait to get a second opinion from @Dellxps15 or another member thats ok ,it is quite hard to solder,you need lots of flux and put new 60/40 solder on the pins.With such small pads its easy to damage the pads,don`t have the iron too hot,use lots of flux,run the iron across all the pads at once or with a fine tip and solder do one pin at a time.

[piernov]

Re: Dell Inspiron LA-D801P Motherboard completely dead

UZ3 has a center pad so you need hot air to remove it/put it back on the board. With hot air, good flux and good solder (and maybe a bit of practice) it's not hard to solder those back though.
There's usually a lot of stuff on the +3VALW line (and quite a few of those components can go bad) so your best bet is to inject voltage and check what gets hot.

[SMDFlea]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Edited.

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

@SMDFlea i'll probably remove it.I don't see other option.
@piernov yes mate i use hot air, this way i removed the PU100 before and solder it back.
I was thinking about injecting voltage too to be honest, do you believe it's a good idea or should we leave it as last option?

[SMDFlea]

Re: Dell Inspiron LA-D801P Motherboard completely dead

As piernov rightly said there are many parts on the +3VALW line.A few of those parts besides UZ3 are UC5,6,7,9 UA1,JPWR1,UL3 you can do a quick visual check on those or just inject voltage

[dellxps15]

Re: Dell Inspiron LA-D801P Motherboard completely dead

if u have a lab psu, put 3 volt and solder on shorted side of pjp102. stay 5 seconds then power psu off and check wich part of board get hot... then power on again for other few seconds and try to figure out what is in short.

could be a bad pch, but u need lab psu to see where the short is.

with power supply, u have 3.3 voltages on battery connector ? (without battery)

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Hello again.
Got a little problem with my connection but now it's back again.
Yes i got a lab psu, i set 3.3v at 3A and found that a small SMD is getting really hot, it looks like a capacitor and i remove it, it's shortcircuited indeed.
Problem is that i don't know what capacitor is to replace it.
Check attached picture please.

[dellxps15]

Re: Dell Inspiron LA-D801P Motherboard completely dead

check if without capacitor , and maybe new 3.3 volt ic notebook is working again.

edit:

make a picture with marked zone of opposite pcb layer in that capacitor zone.

[piernov]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Not sure what value it is, maybe 10uF. The board may work without it, but try to take a capacitor from a 3V line of a donor board that's of the same size to replace it.
This section looks like to have been badly damaged by the liquid. You should take note where the liquid hit the board before cleaning everything.

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

No it doesn't work, 3.3v are not back.
Perhaps the capacitor is reuired in order to get 3.3v?
The liquid hit on the other side of the board, was plenty so almost all other side needed clean.
Picture of the other side of the capacitor attached, it's under UE1 and kinda left as you see it in picture.
Checking other motherboards for same size cap in 3.3v channel meanwhile.

[dellxps15]

Re: Dell Inspiron LA-D801P Motherboard completely dead

do u know how to find it onboard ?

is it a 0603 or 0805 size ?

those5 big near l100 are 0805 aize. is it same size or a bit smaller ?

if its 0603, look for all capacitors 0603 size on the shotted line "+3VALW", so look for that on schematic and take note of all 0603. then when u find some near ue1 zone, look if on pcb zone there is a 0603 capacitor

example: if we are looking for a 0805 size and looking for +3VALW point u to a pu800 and pc802 capacitor, lookf i near pu800 there is a 0805 capacitor size, if not could be the one shorted.

if u understand what i mean.

lets measure if its a 0603 or 0805 size first.



edit: look that 0805 caps near l100. put soem good flux, hot air and make them solder properly. then clean all with ipa. if short is gone, put psu on, and see if with pressing power botton pc power on.

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Since i removed the capacitor in previous picture the short is gone.
Capacitor it self is shortcircuited, measure it already.
These 4 caps near L100 are these that i removed after one of the initial posts.Soldered ok, checked.
Now trying to figure out the size of the capacitor.

edit: it's a 0603 (1,6mm length)

edit2: check picture.perhaps this is our cap?

[dellxps15]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Since i removed the capacitor in previous picture the short is gone.
Capacitor it self is shortcircuited, measure it already.
These 4 caps near L100 are these that i removed after one of the initial posts.Soldered ok, checked.
Now trying to figure out the size of the capacitor.

edit: it's a 0603 (1,6mm length)

edit2: check picture.perhaps this is our cap?

u have to follow the "+3VALW" line ... capacitor was shorting that ...

and that 0603 is a resistor...

edit: or 10u or 22U is its value.

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

I don't get it mate, what do you mean to follow the 3VALW line?

The green mark not mine, i used the red arrow pointing to 10Uf CE5

[dellxps15]

Re: Dell Inspiron LA-D801P Motherboard completely dead

I don't get it mate, what do you mean to follow the 3VALW line?

The green mark not mine, i used the red arrow pointing to 10Uf CE5

sorry watched wrong point on ur picture. yes ur right. only 10u or 22u capacitors.

so one of those is the right one, but better look for a 0603 capacitor connected to a 0402 capacitor in same line, as in the picture near ue2 zone.

edit" yes looks like the only one close to a 0402 capacitor is that 10uf value

try powering on pc and see if something happens.

[Andreasbest]

Re: Dell Inspiron LA-D801P Motherboard completely dead

Replaced the 10uF. no shortcircuit now but still missing the 3.3v from pin19.
Before we proceed please let me know how can i confirm if i solder PU100 100% correctly?