[SOLVED]820-3476-a no green light no power second time

dam1inc

Member
820-3476-A
Hi, guys, this is my first macbook repair, honestly dont thing i would have made it this
far without watching a bunch of louis rossman videos and pouring thru alot of threads.
Ok, so this board was water damaged and had no power when I got it.
after replacing u5110 I got green light
had short on pp5v_s4..which led me to a short on u6410.
after i replaced that i got the fan to spin...then it died again..no green light
after some searching i found smc_bc_acok was missing...replaced U7100..
Now i have a green light that switches from orange to green and just back and forth..
im missing pp5v_s4 and pp5v_s0 is .024v

I was wondering what creates the pp5v_s4 line? is it u8080
thanks




ppbus_g3h = 12.6v
ppbus_s5_hs_computing = 12.6v
ppbus_s5_hs_other5v = 12.6v
ppbus_s5_hs_other3v3 = 12.6v
ppdcin_g3h_isol = 16.8v
pp3v42_g3h = 3.4v
pp5v_s5 = 5v
pp5v_s4 = 0v
pp5v_s0 = .024v
smc_pm_g2_en = 3.4v
smc_tx_l = 3.4v
 

dukefawks

Administrator
Many many things are needed to get 5V_S4 to come on. Seeing that u6410 was shorted I have a feeling that the 5V rail went high and killed it. Have you checked all other rails for short to GND? Is PPBUS stable? Is PP3V3_S5 present?
 

dam1inc

Member
Hey thanks alot for the reply, heres what i got:

PPBUS_G3H is stable

and supplemental to my first post readings

pp3v3_s5 = 3.4v
pp3v3_s4 = .004v
pp3v3_s3 = 3.4v
pp3v3_s0 = 3.4v
pp5v_s0_fet = 5v

no shorts that i can find, seems im missing pp5v_s4/s0 and pp3v3_s4.
 

dam1inc

Member
got an ultrasonic cleaner this morning and threw the board in that. Now i get fan spin but CPU gets really hot. still nothing on the pp5v_s4/s0 and pp3v3_s4 lines
 

dam1inc

Member
also i just noticed that i can use the power button to turn on the device but only the fan starts to spin
 

dam1inc

Member
OK, im finally getting somewhere...replaced U7501 and now device boots, PRAM reset 3 times, can here the chime on boot BUT no image/backlight :(
 

dam1inc

Member
OMG...OMFG...i fixed my 1st macbook:cool: im so fucking cool lol

replaced U8300 and now all is well..

grammy speech:

I def could NOT have done this without this forum, especially dukefawks and all of the youtube vids provided by Louis Rossmann, so thank you guys for all that you do!!
 
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