820-00165 Doesnt Boot. Green Under SMC

Instafixx

Member
For My Reference Only 7542.

Macbook 820-00165.
Corossion Under SMC.
Cleaned and heated the SMC with flux and the machine turned on and worked for 2-3 hours.

So i went ahead and removed the SMC. Cleaned all the pads. Found trace betweeen R5117 and the SMC corroded. Reconstructed it too. But it doesnt turn on.
I get a fan spin on startup. then it stops. then again spins gradually to max.

No Voltage at R5117 / R5608 / C5602 .

C5433 is 2.3V.

I think some issue with SMC or the traces. What will be the best way to check it rather than being a wild goose chase.
 

2informaticos

Administrator
Staff member
Check diode mode to ground on that corroded line.
Be sure R5117 has correct ohm value; it requires 3V42 presence on the other pin.

Did you resolder correctly SMC?
Use leaded paste for balls.

Check if machine starts in SMC bypass.
 

Instafixx

Member
the corroded line was reconstructed via jumper wire.
R5117 has 3.4V on the other pin.

Ohms Value to Ground.

Pin 1 is 21K Ohms and increasing
Pin 2 is 170k Ohms and increasing

Ohms Value Between Pin 1 and Pin 2 is 100 KOhms - Stable.

SMC Bypass results in the max fan spin as it should but the machine doesnt switch on.
 

2informaticos

Administrator
Staff member
Do you get voltage on CPU core coils?
PLT_RESET_L comes high?

Inspect for corrosion all SPI Bus Termination resistors and their traces.
Clean J6100, if needed.
 

Instafixx

Member
Removed the SMC and checked all the PADs. The top 3 lines diode mode readings are totally out of range barring 2-3 pads.

Example
SMC_OTHER_HI_ISENSE is 0
SMC_CPUVR_ADJUST_ISENSE is 7.7.
SMC_TDO is 2.7

The upper portion of the SMC had the green corrosion.

Do we have to reconstruct all these traces ?
 
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