A1707 20V 0.01A and does nothing.

[Enzo150i]

Hi all,
we have a MacBook A1707 with 820-00928-A motherboard that switches to 20V but drain just 0.01Ah.
Customer declared that this machine is used "as desktop" (always connected in the wall, and nearly never moved from his spot). No signs of liquid damage or burns inside, but there's a low resistance on PPBUS_G3H.
Injecting 1V makes PCH to immediately heat a bit (picture attached), so I guess there's a shorted mosfet or something like that somewhere. We still not removed the heatsinks to check if this happens on CPU/GPU too, but I'm here to ask were to start to inspect at least for PCH because there's no direct connection at all from PPBUS_G3H and PCH's mosfets (instead, CPU and GPU have theyr shunt resistor between PPBUS_G3H and mosftes, but for PCH I got lost, lol).

Thank you.

[reformatt]

I'm not following exactly. PP1V0_SUS is generated from PPBUS_G3H via U8000. From your thermal image I would say your PCH is toast as the heat in towards one edge/corner. Normally PCH should measure at least 50 ohms or more on that power rail at ambient temperate (resistance goes down if board or chip is hot). If the PCH is dead, you won't get PM_SLP_S4 etc.

[reformatt]

I'm not following exactly. PP1V0_SUS is generated from PPBUS_G3H via U8000. From your thermal image I would say your PCH is toast as the heat in towards one edge/corner. Normally PCH should measure at least 50 ohms or more on that power rail at ambient temperate (resistance goes down if board or chip is hot). If the PCH is dead, you won't get PM_SLP_S4 etc.

[Enzo150i]

I'm not following exactly. PP1V0_SUS is generated from PPBUS_G3H via U8000. From your thermal image I would say your PCH is toast as the heat in towards one edge/corner. Normally PCH should measure at least 50 ohms or more on that power rail at ambient temperate (resistance goes down if board or chip is hot). If the PCH is dead, you won't get PM_SLP_S4 etc.

Yeah, U8000 were shorted. I feel bad about the PCH. Didn't check the resistance yet (just removed the U8000 and checked PPBUS_G3H), but I guess it's gone :/

Thank you!