820-4927 - liquid damaged, green, orange light, not turning on.

Alan.L

Member
PPBUS_G3H : 12.56
PP3V42_G3H 3.411
SMC_RESET_L : 3.38v
PPVRTC_G3H 3.295v
PP5V_S5 : 5.038
PP3V3_S5 3.347
PM_SLP_S4_L : 0v
PPVCC_S0_CPU : 0v
SMC_LID High : 3.345
ALL_SYS_PWRGD: 0v
SMC_BC_ACOK: 3.381v
PP1V05_S0_REG - 0.3v

u7100:
17/18 - 3.6ohms
27/28 - 20.5ohms

PP3V42_G3H - resistance to ground : 36kohm


Corrosions on u1900, u7100, u7600, Q7010
minor corrosions on Q7630, u7310, Q7310, Q7320
R5488 - pin2 was burnt. (next to SMC)
keyboard - pin4 - was burnt (PP3V42_G3H)

i have replaced the stuff above already. PP3V42_G3H is little low.


dead SMC, any ideas?
 
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dukefawks

Administrator
First check the usual suspects U1950 pin 8, U6100 and termination resistors in the data lines and the traces/vias to U6100/termination resistors.

Corrosion on U7310 is worrying though, CPU is very easily killed. What is resistance to GND on L7310?
 

Alan.L

Member
U1950 pin 8 - 3.411 - corrosion was on pin8, i replaced U1950. made no diffiernces

resistance to GND on L7310 - 28.7 ohms

i'll checked all resistors on SPI Bus Series Termination. all perfect.
 

Alan.L

Member
did a USC, after drying. i was able to perform a smc bypass. i could hear chime, fan spin. vcore was 1.8v.

now it is hard to get into smc bypass, sometime work, most of time doesn't.

i also notice pubs_g3h sometime become 12.23v
 
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Alan.L

Member
ok, i've just reflowed smc

now it posts without doing a smc bypass,

i'll do more test and might need to change smc...

fan doesn't spin in normal mode with this model?
POra7Un.jpg
 
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aprendiz

Moderator
Check if voltage on PPBUS_G3H is still on 12.23V, if yes you may need to replace SMC..

On this model fan will not spin untill processor is burning so dont worry about it....
 

Alan.L

Member
yes its 12.58. hope it stays.
RAXSjMJ.jpg





it currently doesnt have a battery installed due to swollen.

i need to buy a replacement battery.

i'll come back to this thread in a week or so..

no issues on osx, no high fan or anything odd. probably be ok. *Fingers Crossed*


please leave this open...
 
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