Search results

At 5W even the CPU die should get noticeably warm. Did someone try to reflow the CPU?

Don't touch the side that's power cycling, it's fine. It's the other side that's stuck at 5V without cycling that's causing trouble.

Sounds like SMC issue if SMC_DELAYED_PWRGD doesn't come up.

Check resistance to ground and diode mode to ground on SMC_DELAYED_PWRGD.

https://mega.nz/file/JMAygTrS#d746vYBhbRmfdAq64EwXKa2dGjgVv0--XBjfpjue5nI

Check for liquid damage/corrosion on U1950. Check voltage on all pins of U1950.

PLT_RESET_L?

Dead GPU.

Check FSB_CPURST_L and PLT_RST_L. Try to flash SPI ROM.

Did you check continuity as instructed?

Board number is 820-00850. It's written on the board. 20V (on USB-C) at 0.5A to 0.8A is 10W to 16W, not 40W to 48W.

A1237 has Intel GMCH/ICH while A1304 has NVidia MCP.

PPBUS_G3H at 8.4V is fine. Power button must be triggered for machine to turn on. If it doesn't turn on go through the list of power rails.

I hadn't noticed that behaviour before but indeed when measuring CPU_VR_READY on a 3476 board will often turn off after removing the probe (and sometimes when measuring). Not sure why and if it's an indication of anything. I can still often measure 1.05V when touching with the probe initially.

Linux camera driver is more verbose than macOS and shows you some initialization steps in the kernel log. It may or may not help narrowing down the problem.

Try Target Disk Mode to backup the data.

As far as I know they all have the RAMCFG annotation, the schematics list some configurations but I'm not sure if they are 100% accurate.

It's fine but you also have to match the RAMCFG strapping resistors with the donor board. Check if R1631/R1636/R1635/R1611/R2050/R2051/R2052/R2053 are populated or not on the donor board and replicate on the recipient board.

ALL_SYS_PWRGD, CPU_VR_EN_R, PPVCCSA_S0_CPU?

There's a bug running AHT or ASD EFI on some older machines that got Mojave BootROM update. (for some of them the bug was fixed with a later update) ASD OS runs fine. Exclude software issue first. Also U8900 solder joints rework.