Dell XPS 15 7590 - Powers via USB-C but not AC (missing PS_ID?)

[coputerdiscount]

Hello I have a Dell XPS 15 7590 motherboard that acts precariously after liquid damage near its charging circuit:


EDP51/EDB51 LA-H331P is the board, and I will upload schematics and boardview when I get home to help my dear friends here on the forum!

Board view found here:
https://www.badcaps.net/forum/troubl...-1-0-schematic

After cleaning the area and lifting components and cleaning pads etc (sorry I don't just replace the components, I don't have a donor board at the moment), I find no increase in functionality.
Currently I find that the computer does not recognize the AC adapter as being attached what-so-ever. Plugging in a 65W USB-C charger allows the machine to charge while the machine is off. I assume that a 180w USB-C might be able to charge it while its on as it recogizes the charger while the laptop runs however it tends to drop connection at random in which I presume the 65w is simply not putting out enough power to keep the machine charging(?).


I am unfortunately not familiar with dells PS_ID technology, but what I can say is after plugging in the charger I read nothing on the PS_ID circuit when the laptop is in standby.

I'm at work right now so I figured I would get this post rolling and after some suggestions and questions I'll update when I get home and can probe more.

My equipment:
Fluke 101 multimeter with micro probes
Quick 861DW hot air station
Hakko FX soldering Iron
A modest scientific analog microscope

[mon2]

Grab some IPA (alcohol) from Costco pharmacy on the way home and use with a cotton swap / Q-tips to clean up this region. Then post fresh pics. It should help.

[coputerdiscount]

Grab some IPA (alcohol) from Costco pharmacy on the way home and use with a cotton swap / Q-tips to clean up this region. Then post fresh pics. It should help.

I took it a step further than that, reflowed, pulled the mosfet and the package above it and cleaned underneath them. Bare in mind this was a coke spill (of course it is..) so there will be that tacky residue that just will not come off with even the stiffest of bristle brushes. I did not pull and reflow the ISL, as it looked relatively pristine.

Here is the cleaned area, side note the transistor to the top left of the isl was cleaned after the photo was taken:


I do not read any obvious shorts with any of the SMD capacitors, the big 3 above the mosfet while they look bad, are not short.

[coputerdiscount]

Edited first post with Schematic and boardview for similar board (LA-F541P) as LA-H331P are paywall or not find-able.

After sitting through a handy video:
LAPTOP REPAIR - DELL PSID - SHOULD HAVE 3 3V? (youtube.com)

I realize that PSID is a signal, not a voltage. So I'm not looking for 3.3v on PSID, and rather I wish I had a DSO so I could check it. Instead I will have to make sure 5VALW is present going to PR104 and that it is 10k ohm.

I do have concern for the IO chip as I did notice that sound in windows seemed not very great quality. I know that AUDIO_AMP_SMBDAT and PS_ID live on UE3 (IO chip) so I do have some mild fear that UE3 was damaged..

[SMDFlea]

Edited first post with Schematic and boardview for similar board (LA-F541P) as LA-H331P are paywall or not find-able.

If the schematic is posted here at badcaps post a link to it,don`t attach it to this thread please.

Reminder: rules and organization of this section
https://www.badcaps.net/forum/troubl...f-this-section

[coputerdiscount]

Is it known what HW_ACAVIN_N is typically?

On PR 211 1.1m ohm is read, which there is no voltage coming from the other end going to Pin3 on PU200A.
PU200A is a voltage comparator, so I wonder if thats the cause of no AC detection.

I am also missing +3VALWP and +5WALWP

Considering I dont have an DSO and I'm missing 3v5vALWP , they're triggered by ALWON via the IO chip. I'm highly considering that the IO chip is bad.

[coputerdiscount]

Went ahead and re-checked PU200 as HW_ACAVIN_NB comes from it, that being said pin 3 shows 0v.

Pin3 connects to PR211, at the other side is 19v from +DC_IN. I measured the resistance of PR211 and found a reading of 720k ohms, far from the 240k ohms listed in the schematic.

Will have to track down a 240k ohm smd resistor and find if I can restore HW_ACAVIN_NB.

[mon2]

Review the resistance of this part when it is off the logic board. Digikey is a good source for smd parts with overnight shipping. Be sure to purchase the right smd size = 0402 or 0603 or 0805 or 1206. Schematic should reference the case size.

Consider to also purchase the other resistor on this voltage divider. They should be inexpensive from Digikey.

[coputerdiscount]

Review the resistance of this part when it is off the logic board. Digikey is a good source for smd parts with overnight shipping. Be sure to purchase the right smd size = 0402 or 0603 or 0805 or 1206. Schematic should reference the case size.

Consider to also purchase the other resistor on this voltage divider. They should be inexpensive from Digikey.

Got the new resistor. Good news it sees the charger now.

Bad news: when windows loads the system charges for about 5-10 seconds and then the charger light goes off and it stops sensing a charger as if the charger has shorted.

Oddly enough while in bios or powered off, it charges just fine.

It ALSO will power the machine indefinitely without a battery attached.

Really puzzling. Could this be an ISL issue?

[mon2]

No. 65w adapter is not suitable to run and charge this unit. Test with 130W or higher. update this thread after you do.

https://www.xda-developers.com/best-...hargers%20only.

[coputerdiscount]

Hello! I'm using a dell 130w oem barrel adapter.

I have a 90w usb-c that I'm using to test basic function and in my experience as long as nothing stressing is being done it should still charge the machine? Anyways the usb-c is just for isolating a theory that the DCIN circuit is to blame. But again the USB-C charger drops constantly. FWIW I'm willing to agree a > 130w usb-c adapter COULD be necessary.

Same results. Within windows, the 130w oem charger appears to "short" and the light goes off on the end, the laptop stops seeing the charger.

[mon2]

What does the bios report regarding the power adapter? Is it able to recognize the adapter to be suitable and 130w? If not, the ps_id line is not working. From my understanding, dell models report the detected power adapter details in the bios.

[coputerdiscount]

What does the bios report regarding the power adapter? Is it able to recognize the adapter to be suitable and 130w? If not, the ps_id line is not working. From my understanding, dell models report the detected power adapter details in the bios.

Turns out, the XPS7590 IS picky. If I had diagnosed better and just hooked up my external PSU I would have realized that this machine will ONLY work with 130w or more adapters.

I grabbed another dell 130w OEM adapter and whala, it charges in Windows consistently. Turns out the original AC adapter went sour somehow, and when peak draw was taken from it (when it gets into windows and processes stuff), it crapped out. System works just dandy with new AC adapter. Go figure.

[mon2]

Your external PSU will not pacify the 1-wire (Dallas Semiconductor / Maxim specification) communication that exists inside each Dell branded power supply. That is required to properly identify the ratings of the power supply.

[coputerdiscount]

Your external PSU will not pacify the 1-wire (Dallas Semiconductor / Maxim specification) communication that exists inside each Dell branded power supply. That is required to properly identify the ratings of the power supply.

Fair enough. Still very interesting the 130w failed in a weird way.