1278 820-3115-B no grrenlight

[hgoncalves]

Hi,

I have an A1278 820-3115-B that has no power.
I don't get green light or fan spin.

I have 3.32V on PP3V42_G3H
3.23V on SMC_BC_ACOK_VCC

U6900:
2,73V Sys_onewire
2,72V Adapter sense
3.29V SMC_BC_ACOK_VCC

Already tried with new charging port.

I imagine that the problem is related with this mesuarements (PP3V42_G3H). Am i correct? Can you help?

 

[2informaticos]

Is the SMC runing?
Post exact PPBUS_G3H voltage, without battery.

 

[hgoncalves]

HI,
PPBUS_G3H =12.26V

 

[2informaticos]

Check SMC_RESET_L and Y5010.

 

[hgoncalves]

Hi,
SMC_RESET_L oscilates in between 3.28V and 3.3V
Y5010 oscilates in between 40 and 360kHz

 

[2informaticos]

You must get 12MHz at Y5010.
Post its DC voltages.
Check resistor, capacitors and traces.

 

[hgoncalves]

It is oscilating between 0.5V and 0.9V

SMC_XTAL_R = 0.50V
SMC_EXTAL = 0.50V

Traces between C5010 and SMC_EXTAL are OK, and btween R5010 and SMC_XTAL_R also OK. R5010 has 2.49 kohm to ground
Shall I replace Y5010?

 

[2informaticos]

Check power and signals for U4900 (2 OF 2), page 45.
You may need to reball, or change SMC.

 

[hgoncalves]

You're right. It was a bad SMC.
TKS!