MacBook no chime or boot but green light and fan on charger (820-3787-A)

[koby058]

hi

when connecting power : green to orange light on charger
after a few seconds fan stop and the start and remain spinning
Laptop is water damaged corrosion was cleaned

Can someone please help testing it?

known voltages

PP3V42_G3H - 3.41
PPBUS_G3H - 12.49
PP3V3_S5 - 3.32
PM_SLP_S4_L - 3.3

[koby058]

Re: MacBook no chime or boot but green light and fan on charger (820-3787-A)

Hi

Attached Schematics

The minute i touched the pin on the pic while searching for ALL_SYS_PWRGD

The fan stopped spinning and no green to orange anymore

Voltage on L7130 is 12.18V and Motherboard dead

Can someone advise why when touching this pin with probe the MOBO died ?

Also, can someone advise how to continue now ? is it hopeless ?

[mon2]

Re: MacBook no chime or boot but green light and fan on charger (820-3787-A)

ALL_SYS_PWRGD is an open drain output built up from other power good rails.

If any single power good is not ready, then will be a LOW output.

That is every power good creating the single ALL_SYS_PWRGD status must be good = high impedance to function. This ALL_SYS_PWRGD requires the presence of a pull up resistor. Search for it and confirm the resistor is not defective from corrosion.