Dell XPS 9310 stuck at 5V

[sauce]

Hi,

My Dell XPS 9310 (motherboard LA-J143P) is stuck at 5V 170mA on my USB-C meter.

I checked all voltages on the 2 PD controllers and all are good.
I checked with my oscilloscope and I have a communication on CC lines.

For now the only thing I found it's :
- the EC chip is quite hot with thermal camera around 30°C
- PR208 (a 2R2 resistor) is a little burnt but still measure good. This resistor goes to intersil charger chip on DCIN

I am not an expert on PD controller and USB-C I don't know what to test next.

For me it's seems to be a EC chip issue because it's the only thing quite hot on board but how to be sure ?
Is PD controller needs EC chip to negociate the 20V ?

I tried with another charger to be sure and it's the same.

I have an oscilloscope so I can check if there is communication but where to check ?

https://www.badcaps.net/forum/troubl...49#post3479849

[mon2]

Measure the voltage to ground on each leg of pr208.

[sauce]

Some kOhm and it goes up.
All voltages on ISL are good.

So i don't understand why this resistor is slighty burnt the only thing behind is ISL.

[mon2]

Best to post the actual voltage measurements. If really burnt then too much current went through this part.

[sauce]

Ok i will post voltages of ISL and pd controllers.

Do i need to plug the battery for ISL measurementv?

[mon2]

For now, leave the battery disconnected. The power adapter on its own should be able to power the logic board.

[sauce]

Here are the voltages of the ISL9538C without battery connected :

1. CSON 8.38V
2. CSOP 8.38V
3. VSYS 8.38V
4. BOOT2 9.74V
5. UGATE2 5.38V
6. PHASE2 4.9V
7. LGATE2 0.35V
8. VDDP 5V
9. LGATE1 0
10. PHASE1 5V
11. UGATE1 10.3V
12. BOOT1 10.3V
13. ASGATE 0
14. CSIN 4.9V
15. CSIP 4.9V
16. ADP 4.9V
17. DCIN 8.08V
18. VDD 5V
19. ACIN 0.9V
20. CMIN 0
21. SDA 3.3V
22. SCL 3.3V
23. PROCHOT# 3V
24. ACOK 3V
25. BATGONE 0
26. CMOUT 0
27. PROG 0
28. COMP 1.5V
29. AMON/BMON 0
30. PSYS 0
31. VBAT 0
32. BGATE 8.38V

[sauce]

UPD1 voltages where the power adapter is plugged :

1. LDO_3V3 3.4V
2. ADCIN_1 0.3
3. ADCIN_2 0
4. LDO_1V5 1.5V
5. GPIO0 0
6. GPIO1 0
7. GPIO2 3.2V
8. I2C_EC_SDA 3.3V
9. I2C_EC_SCL 3.3V
10. I2C_EC_IRQ 0
11. I2C2s_SDA 3.3V
12. I2C2s_SCL 3.3V
13. I2C2s_IRQ 3.3V
14. GND 0
15. DRAIN_1 4.9V
16. I2C3m_SDA 3.4V
17. I2C3m_SCL 3.4V
18. I2C3m_IRQ 3.4V
19. GPIO3 0
20. PPHV_1 4.9V
21. PPHV_2 4.9V
22. PPHV_3 4.9V
23. VUSB_IN1 4.9V
24. VUSB_IN2 4.9V
25. VUSB_IN3 4.9V
26. GPIO4 3.4V
27. GPIO5 0
28. CC1 1.6V
29. CC2 0
30. DRAIN_2 4.9V
31. GND 0
32. VUSB_1 4.9V
33. VUSB_2 4.9V
34. PP5V_1 5V
35. PP5V_2 5V
36. GPIO7 3.3V
37. GPIO6 0
38. VIN_3V3 3.3V

[mon2]

These measurements look ok to me.

The PD controller @ UPD2 is responsible to negotiate the 20V power delivery (PD) contract that is absent in your case. You have the power up default of 5 volts only present and that is not enough to power the board.

Carefully review the voltages on the UPD2 controller to confirm that it is being powered.

Next, remove all power -> meter in diode mode. Red meter probe to ground (yes red). Black meter probe to the point to test.

Measure the CC1 and also the CC2 pins in diode mode. We are checking if the CCx lines are not damaged because it is these pins that negotiate the PD contracts to / from the power adapter.

The firmware to operate the PD controller appears to be injected by the EC and/or PCH.

It appears that the EC has IRQs that it services when there is a request made by the local PD controllers - one for each USB C port.

Have you tested to power the board using the other USB C port? Do also attempt to rotate the power adapter mating connector by 180 degrees which then exercises the other side of the USB C blade. Do this with only the AC power removed. Disconnect from the wall, flip the connector by 180 degrees -> mate with the port to test -> now plug in the power adapter. Do not trust USB C as far as I can throw it. The PD spec 1.0 almost burnt my hands when we tested it upon initial release. Crapware.

[sauce]

CC line are ok because I can see communication with my oscilloscope as I said.

I also rotate the power adapter and it's the other CC that is 1.6V.
The both ports behave the same.

But I test I have no communication between EC and BIOS is it normal ?

[sauce]

Unbelievable I found !

XTAL YC1 near the SSD was damage ! The top was very strange and bingo.

I replaced it from another dell motherboard and the motherboard is coming.

But a strange thing the usb meter was still at 5v, I unplug battery and replug it while the power adaper was plugged and now I have 20V !

Still now picture with mu usb-c hdmi but maybe it's normal.

Thank you I will be back if I have still no picture

[sauce]

I have picture BUT the laptop stays on the DELL logo !

I've seen a lot of issues like this on forums do you know why ?

[mcplslg123]

Are you running with all peripherals attached?If yes, remove keyboard,wifi,touchpad ,usb extension etc etc.
Could be bios/ec firmware.
If all these fails very likely EC chip itself is bad.