Dell Latitude 5520 no power

[vpower]

I have this motherboard SouthPeak15 TGL MB 8L, no power and no charging light when connected to a working charger. I found the schematic and the boardview in this forum, the laptop is almost now and seems different from older models - charger is type C for example. Any hint? Thanks in advance.

[mcplslg123]

No info,no measurements?20V reaches to CLR?
If you have a usb-c meter,check whether it is stuck at 5V or not .

[vpower]

No info,no measurements?20V reaches to CLR?
If you have a usb-c meter,check whether it is stuck at 5V or not .

I bought a USB-C meter, no current - 0 ampere when connected to working charger.
I'm having some troubles in finding the CLR resistor on the motherboard, can you help me with the attached boardview file? I could also attach the schematics if needed
Thanks in advance

[SMDFlea]

I bought a USB-C meter, no current - 0 ampere when connected to working charger.
I'm having some troubles in finding the CLR resistor on the motherboard, can you help me with the attached boardview file? I could also attach the schematics if needed
Thanks in advance

Schematics and boardviews should be linked to and not posted in laptop troubleshooting threads

https://www.badcaps.net/forum/troubl...his-section

[mon2]

What is the voltage on the usb C meter? Or is the meter dark?

Rotate the USB C connector by 180 degrees and test again.

[vpower]

please check photos. rotating the connector or changing the port is the same.

[vpower]

Schematics and boardviews should be linked to and not posted in laptop troubleshooting threads

https://www.badcaps.net/forum/troubl...his-section

here I found schematics and boardview:
https://www.badcaps.net/forum/troubl...19-1-schematic

[mon2]

Next, test the other USB Type C port on the logic board. Same results?

At 5v, this is the power on default from the external PD (power delivery) adapter. No current is being drawn so there is a fault in the power path from this external power source and the load = logic board.

You can also power this unit with a standard barrel type power adapter - has that been tested?

[vpower]

same result on both type c ports. no standard barrel type power adaptor present - type c charger is the only way to charge the laptop

[mon2]

Review the voltage to ground on each pin of the S4 and also the S5 mosfets that are in the power path from the Type C connector to the charger IC.

Interested in the source / gate / drain voltage measurements. Post each.

[vpower]

do you know the name of S4 or S5 MOSFET? the board is different from usual and I cannot find them in boardview diagram
edit: found thank you

[vpower]

Review the voltage to ground on each pin of the S4 and also the S5 mosfets that are in the power path from the Type C connector to the charger IC.

Interested in the source / gate / drain voltage measurements. Post each.

sorry, I cannot locate S4 and S5 mosfets on the board or in boardview. Can you help me? Sorry I'm a noob

[mon2]

Share the topside markings of the attached devices. Or a clear pic to show the markings. These are most likely the PD (power delivery) controllers. One for each USB Type C port.

[vpower]

Intel JHL8040R

[mon2]

These are the TBT signal redrivers so not what we are after.

Search for Q7407 = 8 pin mosfet used in the power path if using USB Type C connector # 1. Interested in the voltage to ground on each pin of this mosfet when the power adapter is connected.

The PD controller is PTPS65994ADYBGR @ U7201. This part is responsible to select the 20V PD contract from the variable power supply you are using to power this logic board. If the power adapter is at 5v, then this PD controller is not negotiating the contracts properly.

[vpower]

[QUOTE=mon2;n3451099]These are the TBT signal redrivers so not what we are after.

Search for Q7407 = 8 pin mosfet used in the power path if using USB Type C connector # 1. Interested in the voltage to ground on each pin of this mosfet when the power adapter is connected.

Q7407 with charger connected::
pin 1-2-3 5v
pin 4 0.45v
pin 5-6-7-8 5v

[mon2]

Q7407 is working correctly. Confirm the same voltage to ground measurements on Q7408.

[vpower]

Q7408
pin 1-2-3 4,54v
pin 4 4.19v
pin 5-6-7-8 4.99v

[mon2]

The Texas Instruments PD controller (datasheet is available from their website) has a few power rails that must be present to power this controller. Only if the chip is properly powered + the firmware inside the flash rom @ U7202 is not corrupt will the 20V contract be negotiated. Otherwise, the default power up contract of 5V will be presented to the USB Type C connector.

Check if each of the power rails on the PD controller are present. You can probe at the capacitors that are on each such rail.

Check if the firmware rom has power @ pin # 8 = Vcc.

The green checkmark = these are the PD supplied power rails from your adapter and they are OK. The yellow marked rails are of concern.

[vpower]

U7202 is factory empty, I checked all solder pins and 5-6 I have 3.42v. others 0v
5v_s5 on c7226 is 0v
3d3v on c7202 is 0v
1d5v_LDO_PD on c7224 is 1.6v