820-00165 no power, no green light

[kevinklinkmuller]

Hi there amigos
I have a 00165 here with what I thought was going to be a basic no green light repair but it's turning into a rabbit hole. There was corrosion around SMC, no much. PPBUS_G3H is low at 8.16v PP3v42 is actually just consistently 3.41.
SMC_RESET_L is on 3V
Have replaced SMC. same issue. I looked around j9500 and all looks good, reinforced the solder joints on it just in case.
Have also replaced isl6259

 

[2informaticos]

You should get correct PPBUS_G3H without LIO flex connected; even no Magsafe light in such case.

Post voltage and diode mode to ground at SCL/SDA lines of battery bus.
Check components and traces continuity around SMC.
Is AVREF_SMC present?

 

[kevinklinkmuller]

Oh I see, that's good to know.
both lines are 0.5 in diode and 3.41 in voltage
PP3v3_S5_AVREF_SMC is 3.3 yep

All around the SMC is checking out OK, I've specifically also replaced R5100 because it looked a little toasty, but it did measure fine even before

 

[2informaticos]

Post diode mode readings with 3 decimals; less than 1% difference is allowed.

Do you get 12MHz oscillation at Y5110?

 

[kevinklinkmuller]

diode for both is 0.499

I don't have an oscilloscope so I just straight up replaced Y5110 but have the same result

 

[kevinklinkmuller]

is it possible at all that both SMC's are actually faulty in the exact same way?

 

[2informaticos]

Post DC voltages of Y5110.
Working one gets 1-1.2V DC normally...

 

[kevinklinkmuller]

Hmmm strange. pin 1 of Y5110 is getting 1.7V every other pin is getting 0v

 

[2informaticos]

Check directly on SMC_E/XTAL lines.

 

[kevinklinkmuller]

sorrry, i meant SMC_XTAL_R

 

[2informaticos]

Still incorrect PPBUS_G3H (F7140) voltage?
Check it without battery, nor LIO flex connected.

 

[kevinklinkmuller]

yup still 8.18v on f7140 both sides. No flex connected

 

[2informaticos]

Do you now get 1-1.2V on both SMC_E/XTAL lines?

Try known good working SMC.
Once removed, assure to have good traces under it.

 

[kevinklinkmuller]

I get 1.6V on SMC_EXTAL and 1.2 on SMC_XTAL_R
Does 1.6 seem too high to you?

Ok will try another SMC

 

[kevinklinkmuller]

Another SMC, no change. I guess this is a no fix

 

[2informaticos]

Check voltage and signals for U5000 (2 OF 2) at page 37.

 

[kevinklinkmuller]

The only strange thing I've found there is that PP3v3_S5_SMC_VDDA is 3.415V just like the PP3v42 line. So PP3v42 is not quite 3.42 and PP3v3_S5_SMC_VDDA is slightly too high. Not sure if im nitpicking here but I always saw the pp3v42 line as an almost perfect 3v42 on other MacBooks

 

[2informaticos]

"PP3v3_S5_SMC_VDDA is slightly too high"
Not at all; it comes directly from 3V42_G3H (L5001).

If all good there and SCL/SDA lines of battery bus work, then PPBUS_G3H (F7140), should reach 8.5V.
If not, only remain U7100 and SMC as suspects.
Be sure R7100 is good.

Does the fan start normal speed, or directly max speed?