[SOLVED]820-3437 - turns on but slow, Faulty sensor (PC0R)

RedDemonic

New member
not sure where to look on the schematic.


i've found corrosion on pin2 of U5110 - replaced
i've found corrosion on pin8,9 of u8005. - replaced


maybe i have a dead smc?

 
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TCRScircuit

Super Moderator
Staff member
Look at page 41 of the schematic. R5450, U5450 etc... Check all of that .. Check U5430 and its corresponding circuit as well
 

TCRScircuit

Super Moderator
Staff member
Not 100% sure but schematic has nothing for PC0R so my guess is PC0R is based off of a reading from something in the IC0R circuit
 

RedDemonic

New member
R5450 is ok
R5455 is ok
R5451 is ok
U5450 is ok. has 8.58v on pin4,5. 3.3v on pin3


R54301, U5430 are non-stuff. pin3 has 3.3v
 
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RedDemonic

New member
checked traces from U5450 to R5450, all good. i even have replaced both, just to be sure.

any more ideas? dead cpu?


---------------------------------


one thing i've just notice.. when i put back into the case. connect all cables and battery. It will turn on automatically every-time when i plug the magsafe.

i know 2013,2014 air, turns on automatically without a battery connected and only once when connected with a battery.

but this has known good fully charged battery and it still turns on automatically. i've tired without trackpad flex and it still does it.

please watch my video, https://www.youtube.com/watch?v=mdRwDpt6Y-0
 
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RedDemonic

New member
R5455
-------------------
pin2 = 1.513v
pin1 = 0.132v

The corrosion was on pin2 of U5110 - this was replaced which i've stated on the 1st post.



just compared with a known working board =

R5455
-------------------
pin2 = 0.130v
pin1 = 0.129v
 
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RedDemonic

New member
i've reflowed the SMC and (PC0R) have PASSED in ASD :)

Was kinda knew it was SMC but need to confirm with you before i do sometime like this..



The laptop still turn on every-time i plug in the magsafe with a fully charged battery connected any idea and even without a trackpad flex connected?
 
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RedDemonic

New member
does osx save sleep state to bios? i've just shutdown within osx, plug magsafe and it no longer turn on its own.

job done. cheers :)
 
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