820-2879 no magsafe

[MDY]

This macbook pro has no magsafe and I found

U6900
SMC_BC_ACOK_VCC - 3.3V
SYS_ONEWIRE - 3.3V
ADAPTER_SENSE - 7.26V

This means bad SMC?

 

[Cocobill]

Hi, I am new to board repair myself but never heard of the term "no MagSafe". To start diagnosing you need an original Magsafe charger, and a known working DC-IN board. A possible scenario would be: "green light in the charger but no fan spin"

 

[MDY]

Yes, I mean not green light. PPBUS is 12.56V

 

[dukefawks]

ADAPTER_SENSE at 7V means either a bad magsafe board or crap under the connector on the board. Somehow voltage is leaking into it, it should never be over 3.3V.

 

[MDY]

Yes was bad magsafe board. I replaced it and now I have good green light and smc_adapter_en.

PP3V3_S5 - present
PP5V_S3 - missing
No fan spinning.

 

[aprendiz]

This board does not auto power on, use power pads and see what happen...

 

[MDY]

Yes, I know that. This is MCP board. Not i5-i7
I short to ground onoff

 

[aprendiz]

Resistance to ground on pp3v42_g3h, resistance to ground on pins 1 and 4 from Y2810???

 

[MDY]

pp3v42_g3h - 8K

Y2810 20M and infinity.

PP3V3_S5 - present
PP5V_S3 - missing
No fan spinning.

 

[aprendiz]

seems a dead MCP.....

 

[MDY]

Are you sure?? Why do you think so?

 

[aprendiz]

Resistance on PP3V42 is too low, should be about 30-45K, I know this for experience.... But if you want to feel more comfortable, Dukefawks told me this........ That said I hope now that you believe me...

 

[dukefawks]

I don't believe you Aprendiz!

Yeah 8K on 3V42 is usually a dead MCP.

 

[aprendiz]

lol........

 

[MDY]

Today it works. I didnot do anything. Still 8K there. So... still suspect MCP?
Will test 1 week.

 

[aprendiz]

I bet you are measuring with red probe to ground....

 

[MDY]

Red to ground? Why this? In diode mode I measure with red to ground yes. But in normal mode it really matters?

 

[aprendiz]

find out yourself, do the test in both ways, red to ground and black to ground....