[820-00281] dead!!!! 5v@0,48

[mon2]

What is the voltage to ground of PPBUS_G3H? Is it stable?

Measure @ fuse F7000 (both sides).

What is the voltage to ground of ALL_SYS_PWRGD?

Voltage of the following?

SMBUS_SMC_5_G3_SCL ; battery connector
SMBUS_SMC_5_G3_SDA ; battery connector

[phantomEVO]

PPBUS_G3H 12,6 stable

f7000 12,6 both sides

ALL_SYS_PWRGD 0v


SMBUS_SMC_5_G3_SCL ; 3,4
SMBUS_SMC_5_G3_SDA 3,4

[mon2]

ALL_SYS_PWRGD 0v

Means that at least one of the power rails is missing. This is a power good status signal which will be 0v if there is a defective power rail that is being monitored by this circuit.

Measure the voltage to ground on each inductor on the board while powered on. Report any suspects. If you find an inductor with a wrong voltage (off or too low) -> then remove all power. Measure the resistance to ground. Most likely there is a shorted part on that rail - hoping it will be a capacitor.

[phantomEVO]

Where can i find "a list" of the power rails? because i've checked for short on each coil without luck....

a lot of coil have no voltage but i don't know if it is normal...

[mon2]

Let us do this in reverse. Remove all power. Meter in resistance mode. Measure the resistance to ground of each and every inductor. Checking for a lower than normal measurement of the inductor. If found, check the schematic for the rail voltage. If the voltage is a low voltage rail then it is normal to have a low resistance. List any suspects.

[phantomEVO]

ok l7900 is shorted, i've lifted one side, and PP1V2_S3_REG_R is full shorted

[mon2]

Ok. These are dangerous regions and linked to the CPU. Using an adjustable power supply, dial up 1 volt (not higher) and inject onto this rail and point where you are measuring the full short. Which part is heating up? Hoping it is a bulk cap. Keep the voltage low and the current on your power supply as high as possible. Hunting for the part that is shorted.

[phantomEVO]

ok found c423 shorted! removed and mac is alive, now i check with battery!

[mon2]

Crossing my fingers and other parts of the body in anticipation.

Do not forget to place back the resistor "we" removed.

[phantomEVO]

you are the best!!!!!! THE BEST OF THE BEST! IT WORKSSSSSS FLAWLESSLYYYYYY EVEN WITH THE BATTERYYYY!! THANK YOU!!!

[mon2]

Good job!! Hope this thread can help future readers as well.