A1425 820-3462-A no power


I have an A1425 820-3462-A that has no power and no green light.

On PPBUS_G3H I only get 12,28V. Is that a normal value for this board?


Staff member
12.28V means bad communication between SMC and ISL6259.
Do you get 3V42_G3H?
If yes, check then SMC_RESET_L.

I have 3.412 on 3V42_G3H and also on SMC_RESET_L

I don't see any corrosion on SMC or U7000

Pins 10 and 11 (SMBUS_SMC_5_G3_SDA/SCL) on U7000 have 3.4V

SMC_BC_ACOK has 3.22V on U7000
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Sorry but I can´t find in my schematics where to measure SCL/SDA lines of battery bus. Can you please give a reference component?

Y5010 oscilates in between 150 and 700 KHz. Ii seams the it gets, for only a breaf moment 12MHz, but it immediately drops again
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U4900 (2 OF 2) :
SMC_EXTAL = 0.477V
SMC_XTAL = 0.001V
SMC_CLK32K = 0.020V
SMC_TCK = 3.4V
SMC_TMS = 3.4V
SMC_TDO = 3.4V
SMC_TDI = 3.4V
PP3V3_S5_AVREF_SMC = 3.299V
PP1V2_S5_SMC_VDDC = 1.2V