Lenovo Legion 7 16ithg6 NM-D721 weird behavior

[lordmmx]

Hello guys,

I have recently aquired Lenovo Legion 7 16ithg6 NM-D721, with weird issue. From time to time it will POST fine, boot to windows and work without a single issue. After restart however, it will not post again and then it will not post at all.

After messing around with bios (reflashing it), removing ssd, wifi, battery, etc, none of helped, I checked 5v and 3.3 coils and to my surprise, multimeter showed both coils hovering around 4V for 5V coil and 2V for 3.3v coil.

Thermal camera did not showed anything hot, but I'm sure something is either going to fail, or already failed partialy.

I would guess it's KBC/SuperIO, but, i'm not sure.

Any ideas?

Thanks.

[mon2]

5 volt coil will be linked to the dreaded usb vbus rails. Check the usb load switches. Perhaps one is on life support.

[lordmmx]

5 volt coil will be linked to the dreaded usb vbus rails. Check the usb load switches. Perhaps one is on life support.

can you point me where to look [like screenshot from boardview] ? I'm still a noob in reading schematics and boardviews, but I can do the repair when I know what to look for. Thank you