Dell XPS 15Z Won't turn on. (AC Adapter light shuts off)

[FCCAGut]

I have a Dell laptop that said battery is disabled and I plugged it into the wall and the AC Adapter light comes on but when you plug it in the light shuts off in a split second. The power button doesn't do anything. This laptop is OUT OF WARRANTY so I can't get a replacement if there's an internal problem with it. Anyone know what's wrong with it?

 

[C12Friedman]

Repair can even be a DIY thing as this video shows https/www.youtube.com/watch?v=wqCEyGFIdeU
Here's what you're looking at as likely possibilities;
1) power jack has gone bad, this is common enough that companies specialize in that repair and how-to videos are common, like the one I linked.
2) the battery itself is bad and needs replacement (the video shows how to get to it)
Those would be the two most common issues that fit the symptoms although a short anywhere in the laptop would also cause that (but far less likely)

 

[FCCAGut]

So this is what I did.

I removed the bottom case and removed the hard drive, the battery, some miscellaneous connectors, the WiFi card, the memory sticks. With no success.

I checked voltage and it says 20v but after I plug it in and remove it my volt meter says 0.01 volts. This laptop is maybe 3 years old.

 

[ilrenato]

It is an old topic and probably wont help the topic starter. But for future reference I wanted to add I have the same situation. The power circuit of the Dell is prone to static discharges that kill the mosfets (short circuit) so the power adapter turns off by protection. Repower the external supply and it will be blue at the output again.

To fix it you need a repair shop to find the culprit.
PQ100 or PQ101 AO4407A or AO4409
http/kythuatphancung.com/uploads/download/b2f74_Compal_LA-9104P_VAW00_Inspiron_3521.pdf
I used
https/www.youtube.com/watch?v=kdHm8aw2Xro&spfreload=1
to open up the laptop and remove the mainbord, I could then measure the PQ101 to be shorted.
I desoldered it and could then already connect the power adapter again.
I need to replace the part with original AO4409.
http/aosmd.com/pdfs/datasheet/AO4409.pdf
if it is the AO4407A
http/aosmd.com/pdfs/datasheet/AO4407A.pdf
maybe the loader circuit is damaged
http/www.intersil.com/content/dam/Intersil/documents/isl8/isl88731a.pdf

I hope this might benefit others with the same issue.

 

[danmux]

@ilrenato any chance of a photo of the XPS 15 Z mainboard where these usual suspect mosfets might be ?

Or schematics for the XPS 15z in particular

 

[ilrenato]

I had a lattitude 15R, so no xps. You can easily follow a youtube guide to take it apart and then work you way from the power connector.

One thing I did not mention yet in this ticket is the reason why this mosfet dies?
All power circuits (DC/DC) get DC though this mosfet, one of them dc/dc converters will probably have a short, so solely replacing the OA440x will probably not be enough.

 

[danmux]

I had a lattitude 15R, so no xps. You can easily follow a youtube guide to take it apart and then work you way from the power connector.

One thing I did not mention yet in this ticket is the reason why this mosfet dies?
All power circuits (DC/DC) get DC though this mosfet, one of them dc/dc converters will probably have a short, so solely replacing the OA440x will probably not be enough.

Great thanks - actually found a schematic and followed the fault past the first mosfet PQ018 - FDS4435BZ (removed it, it tested good) and find +PWR_SRC to have 7.2ohms between it and ground +PWR_SRC feeds about 5 sub-circuits with a few other mosfets and about a hundred ceramics, Ive removed the main decouplers. Not sure i can be bothered tracking mV drops to find this tho.

 

[neighborhoodsupport]

Hi, I've seen this problem before, the charger chip is probably shorted. bq24765. The chip has built-in fets for the chopping switch. ilrenato is in the ball park, but his model uses a different charger chip which doesnt have internal fets.

Google 'Quanta SS8' for the schematics - page 48 - PU5 is BQ24765.

Fixed mine. If you have questions or can't find the schematics, I have them. You can contact me at gmail as neighborhoodsupport.

 

[Ed_326]

Hi, I've seen this problem before, the charger chip is probably shorted. bq24765. The chip has built-in fets for the chopping switch. ilrenato is in the ball park, but his model uses a different charger chip which doesnt have internal fets.

Google 'Quanta SS8' for the schematics - page 48 - PU5 is BQ24765.

Fixed mine. If you have questions or can't find the schematics, I have them. You can contact me at gmail as neighborhoodsupport.

Hello, I'm having the same issue now with my XPS 15z. I've found PU5 on my board. Are you saying this it is possibly the culprit that is cutting the power when it's applied? Thanks in advance.

 

[ilrenato]

I found the final cause for this issue, short circuit on the board, it is very hard to find a shorted component.
I isolated all circuits by removing the solder bridges, around 7 or 8 PJPxxx in the schematics
b2f74_Compal_LA-9104P_VAW00_Inspiron_3521.pdf
that only learned me that the short did not go away, so it must be real close to the entry.
I singled out where the short then might be and started to remove capacitor PC105, PC106 , PC 104 bingo!!!!
The 4.7U_0805_25V6-K had shorted because of the ESD!
I replaced it with some 1206 cased tantalum cap I had around, had to resolder all PJPxxx joints and the AO4409 that had died because of the short.

Connected PSU and no more switching off
Put all back together and voila!!! It worked again!! Hurray!

Here the same issue and a picture
http/www.badcaps.net/forum/showpost.php?p=578437&postcount=50
Some months ago I searched and found a similar case where this cap was shorted, I guess a common cause for these kind of ESD shorts.

I have some AO4409 and AO4407 left for repair, ping me if you have a need in NL or EU.