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820-3115-B no green light, PPBUS_G3H 12.3V

Atomrepair

Atomrepair

Member
I am also not trusting the SMC job I did. :rolleyes:
Or the SMC I used, of course, but when can you trust that?
I will use my other donor board's SMC for another try as soon as I have time. Will report back latah.
 
Atomrepair

Atomrepair

Member
I finally got around to replacing the SMC again. When removing the previous one, I noticed that three balls had merged. That may have happened during removal, but I probably bumped the SMC too hard when trying to see if the solder had melted while placing it. The merged balls were: LPC_AD<0>, LPC_AD<2> and SMC_WAKE_SCI_L

I grabbed another SMC from a donor board, reballed and placed that. Machine would now power on with quarter fan spin. Magsafe light slightly blinking. Every now and then it would go full fan spin, but no beep from speakers. Most of the time its just an endless loop of quarter fan spin.

I first wanted to rule out having messed up the SMC again so decided to replace it yet again, just to see if the behaviour would be the same. This time there were no merged balls when lifting the SMC, and placing the next one went smooth. The board is acting the same as with the second SMC, so I'm assuming the problem is somewhere else. Might be because of the first SMC job, or because there is simply another issue with the board.

Some measurements I took:

PPBUS_G3H = 12.58V
SMC_BCACOK = 3.27V
SMC_RESET_L = 3.4V
SMC_ONOFF_L = 3.45V
SMC_LID = 3.4V
L7510 = 0V

Resistance to ground because of the previously merged SMC balls:
LPC_AD<0> to ground is about 230KOhm
LPC_AD<2> to ground is 7.18MOhm
SMC_WAKE_SCI_L to ground starts at 1k and goes up quickly
 
Atomrepair

Atomrepair

Member
I hadn't replaced U2600 yet, but I have now. Hasn't changed anything.

R7402/3 are 150/181kOhm
ALL_SYS_PWRGD is pulsing high
 
D

dukefawks

Administrator
At this point it can be anything. Any knocked off component, any corroded trace/resistor. I really have no more ideas.
 
Atomrepair

Atomrepair

Member
I'll inspect the whole thing and see if I find anything of interest. If nothing, I guess I'll have to give up on this one. Hate that :(
 
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