There is USB activity while booting. So might be worth to look at least a little further maybe?

Is there a way to determine if the GPU is...

Checked R7805, is 10k as it should.

So is it certain that it's a PCH issue? This pretty much makes the board unrepairable, right?

I have a 820-3787 board that doesn't display any image, also no backlight activation for that matter.

Someone unskilled has clearly messed...

PPVCC_S0_CPU is 1.098V as stated in my first post.

So apparently it's not surposed to get PPVCC_S0_CPU without ALL_SYS_PWRGD? Is it possible...

Rechecked ALL_SYS_PWRGD, still not present (0.0V). Tested on both R7103 and R7805

Also checked PP5V_S0_VCORE1/2, both are 5.12V.
...

I have a 820-00923-A board that gets into a S0 state, but no fan spin or image. Since I can't find the correct schematic and brd I'm using the 820-00239...

I ordered a donor board from him. Was $15 including shipping, so very good price. Just takes a month to get here
This will have to be continues...

Reflowed the SMC, no change. I don't have a donor board for this, and not sure if it's worth it buying one for this old machine.

I searched...

Checked R5280, seems fine (1990 ohms, should be 2k). Strangly enough I now have 3.42V on SMBUS_SMC_BSA_SDA, and 0.26V on SYS_DETECT_L. I'm a 100% sure...

I have a 820-2936-B board which was completely dead. There was a short on PP3V42_G3H, which was a short internally in the ISL. Replaced the ISL and the...

I'm not sure if I have a compatible known good working LCD. I have a donor A1278 and A1465 with known good LCD assemblies for example. Any easy way to...

*Subtle kick*
Anyone has an idea where to look for the issue?

I've ordered a mini-displayport->HDMI convertor, but I have this feeling...

I have a 820-2850 board that doesn't display an image (checked with a flashlight from the back). Backlight also doesn't work.

There was liquid...