Lenovo Thinkpad T14s gen2i (NM-D362) not starting up after wifi upgrade attempt.

[acedogblast]

After attempting to upgrade the soldered 1216 Wifi module my motherboard no longer turns on. The board works before the upgrade attempt so that would certainly mean some components got knocked off accidentally but I can not find any missing components. I have thoroughly checked the whole board multiple times so lets do some tests from scratch.

Things that currently work:

• USB-C PD for 20V
• Battery charging
• VCC5M and VCC5_PD
• VCC3M
• VCCPCHCORE (1.8V)

I have checked and verified that PWRSWITCH has 3.3V and goes low when pressing the power button. This is measured at the JCAM1 connector. ~LID_CLOSE also is working as it has 3.3V when the lid is open and near 0V when lid is closed.

I have also tried checking the thermal sensors by probing the caps near the EC chip. All but one of them have the same 2.5 to 2.6V. The one that measures strange is C4307 which has 3.3V (this is the EC_THERM_MON1 net). I removed the pull up (R4322) and the thermal sensor(RT4305) and tested them out of circuit and they measure fine. When testing without those components there is still a 3.3V signal at the capacitor. So I then checked resistance between the capacitor to VCC3M which does not show a short as the resistance is over 1 megaohm when the board is not powered. If the board is powered the resistance between EC_THERM_MON1 to VCC3M is 55 ohms.

Does this mean the EC chip is damaged? What other things should I check aside from this potentially faulty EC chip?

I have attached the board-view and the schematic of my board. Link to schematic -> https://www.badcaps.net/forum/troubl...atic-boardview

[rogfanther]

No use measuring resistances with power applied to the board.

Have you removed the new wireless chip ? Can you post pics from that area?

[acedogblast]

Have you removed the new wireless chip ? Can you post pics from that area?

See attached. I have already removed the wifi card but no change when pressing power button.