Lenovo 300-15IBR - No SYSON, no SUSP#, bunch of missing voltages

[mat2k]

Hello, I've been struggling with this one today. I'm troubleshooting a Lenovo 300-15IBR (board BMWC1/BMWC2 NM-A471) that turns on the power LED and does a bit of fan spin but nothing else. 3v3sb and 5vsb present, no 1.05v, no 1.35vddr, no vcore, no 1.8vsb.
BIOS has been reflashed with one I found here, supposedly tested OK by someone else. I don't have an EC programmer unfortunately.
I looked around and SYSON is 0v, SUSP# is 0v too. Forcing them to 3v3 enables the 1.35v rail, but the 1.05v and 1.8v rails are still missing (generated by PU704). EN_1P05A signal is 3.3v, and IN_1P05A is 5v, so I believe everything is there for it to produce 1.05v?
Also the 1.05v rail measures 3 ohms, but the voltage doesn't appear even with the jumper open. Same story with 1.8v.

I would attempt to replace PU704 but the missing SYSON and SUSP signals are also a problem. Any ideas?

[mcplslg123]

Measure resistance to GND on all coils as well as on switched rail side eg 3VS/1.8VS etc.

[mat2k]

1.05v - 3.2 ohm
1.35v - 1.3k ohm
1.8v - 1.4M ohm
3.3v - about 17k ohm
5v - 100k ohm
GFX_CORE - 138 ohm
CPU_CORE - 400 ohm

all on the coils. I'll take a look at the switched rail side later. Thanks for the help

[mat2k]

One more thing to add - I kinda have access to a thermal camera now. Do you think it would be worth it to inject 1v through the 1.05va rail and take a look? It's a relatively high resistance for that voltage, but it could be worth a try.

I am more concerned about everything else (no syson voltage etc.) so I would like to know what you think about those missing signals.

[mcplslg123]

3.2 ohms is too low for 1.05V rail. Very likely PCH is damaged .