[SOLVED]820-3115 Turns on but no green light.

[Therealkilometers]

820-3115 with liquid damage around SMC and SMC_reset. Replaced SMC and it now turns on but powers off about halfway though booting into OS and does not show a green light. Will not turn off if just sitting in boot menu or ASD EFI. Possible Bad SMC?

 

[TCRScircuit]

SMC_BC_ACOK Present?

 

[Therealkilometers]

Yes SMC_BC_ACOK is 3.4v

 

[TCRScircuit]

So it turns off randomly halfway through boot? This one's going to be fun if thats the case.

 

[Therealkilometers]

Yep. But only when booting into OS X. It will sit on the boot menu screen for hours or in ASD EFI. Another thing weird is it will not show sensor test in ASD EFI.

 

[TCRScircuit]

Almost want to say SMC is screwed up software wise but I don't know.

 

[dukefawks]

Could be anything. Corrosion on clock chip, U7400 area and FETs?

 

[Therealkilometers]

U7400 and Clock chip look clean. Tried another SMC and same issues.

 

[dukefawks]

I don't know, it must be a corroded resistor/trace somewhere.

 

[smiba]

Go check out why there is no green light, thats probably the only clue you can do something with at the moment.
When I have a motherboard with multiple issues and I can't resolve one, I move onto the other. Often these are related in a way and I end up resolving both.

Does it never have a charging light or does the light dim after the system powers off? From your post I think always?

What's the voltage of SMC_ONOFF_L and other SMC RESET signals? Often when weird SMC related issues occur this voltage is slightly dropping to somewhere between 2.3 and 2.9V. Also keep an eye on PPBUS_G3H with a fast response multimeter, see if it drops

 

[Therealkilometers]

Alright so SMC_RESET is a constant 3.4V But SMC_ONOFF_L is at 2.4V when the machine is off and 1.3V when its on.

 

[larossmann]

that should be at 3.4v all the time. Bad U5010, bad keyboard, leaky C5710, corroded R5070, or bad SMC. green light isn't on because it thinks you are holding the power button down so it is booting in SMC bypass mode. Good luck hunting!

 

[Therealkilometers]

This board is going to make me go insane lol. Replaced U5010 and SMC_ONOFF_L is back to 3.4V but booting into SMC bypass. Replaced SMC again with nothing changed, C5710 and R5070 looked fine but replaced anyways and still nothing. Is it possible my great donor board SMCS are all dead.

 

[smiba]

What makes you think it's in bypass mode? System no longer crashing halfway through?

If there is still no light on the charger but the function keys work etc. The SMC is probably fine and you should look into fixing the one wire circuit

 

[Therealkilometers]

So I came into the store today and went to work on it again. And everything else works fine now. I have no idea why but ill take it. Thanks again everyone for the help.