820-3476-A Not turnin on. PP5V_S4 shorted to ground

[BCN_Techs]

Hi guys,

Got this macbook with wine damage.

After ultra sonic clear all seems to be ok. There were corrision under Q7430/7560/7520 the where gone after cleaning.


Now getting all rails ok.

ALL_SYS 0V
PP5V_S4 shoted to ground.



U7501 seems to be ok.



P.S. PP5V_S4 must be shorted from any other line. When inject 5V the short is gone and nothing getting warm. From magsafe that 5V is not created.

 

[2informaticos]

"From magsafe that 5V is not created."
???

"PP5V_S4 shoted to ground."
Which is the exact value, on 200ohm scale?
Lift one pin of L7520 and see where remains the low value.
If value increrases after injecting voltage, usually bad ceramic cap.
Inspect all caps from that rail; possibly note some colour change of one...

 

[BCN_Techs]

"PP5V_S4 shoted to ground." Only when magsafe is pluged. Unplug it and the short is gone and resistance to ground are about 4 mln
Which is the exact value, on 200ohm scale? 19.6 ohms
Lift one pin of L7520 and see where remains the low value. Pin 1 is lower 19,6, Pin 2 - 5.5Khms
If value increrases after injecting voltage, usually bad ceramic cap. Actually it decrease after injecting till getting in short with ground.
.

 

[2informaticos]

""PP5V_S4 shoted to ground." Only when magsafe is pluged"
NEVER ever check continuity (diode mode, or ohm scale) on a powered board!!!

So post again the value (diode mode) without any power on board.

 

[BCN_Techs]

You mean post all reails values or just PP5V_S4?

 

[2informaticos]

Post the value for supposed short.
No charger, no battery connected of course.

 

[BCN_Techs]

On L7520 ( with pin 1 lifted) i got 19.6ohms on Pin 1 and 5.5khoms on pin 2

 

[BCN_Techs]

Diode mode ( red to ground) Pin1 : 418 Pin 2 : 398

 

[2informaticos]

"i got 19.6ohms on Pin 1
---------------
Diode mode ( red to ground) Pin1 : 418"
No idea what you do wrong; impossible to get such difference...

No need to lift L7520 if no short there.

 

[BCN_Techs]

i dont know. I put my tester in Diode icon, put red on ground black on pin 1/2 and getting 0.405 ( sorry not 418)

 

[2informaticos]

When you get 19.6 ohms then?
That is aprox 010 in diode mode...
Please provide accurate information...
Seems that there is no short at all.

Do you get magsafe light?
Post PPBUS_G3H and 3V42 voltages.
Check 3V3_SUS and 3V3_S5 presence.

 

[BCN_Techs]

Let's start again

I get green/orange light on charger:

Rails:


PPBUS_G3H - 12.6V
PPDCIN_G3H - 20 V
PP3V42_G3H - 3.42V
PPVRTC_G3H - 3.3V
PP5V_S5 - 5V
PP5V_S4 - 0V / Diode mode: 0.408 / Resistance to ground: 0.5mhoms
PP3V3_S5 - 3.3V
PP3V3_S4 - 0V / Diode mode: 0.475 / Resistance to ground 1,5 mhoms
PP3V3_SUS - 3.3V

PM_SLP_S5_L 0V

No visible damage on board. It had been cleaned in ultrasonic.

 

[2informaticos]

Post now PM_RSMRST_L and check if PM_PWRBTN_L reacts when SMC_ONOFF_L is triggered; use R5115/16 pads.

 

[BCN_Techs]

Pm_rsmrst_l 0v



while posting this message the fan begin to spin and cpu got warm disconected magsafe and conected again few times and fans begin to spin every time. . Mounted it in chasis and not working again.

PM_PWRBTN_L 3.4 V is droped 0V and back again 3.4 when SMC_ONOFF_L is triggered

 

[2informaticos]

Test the board without anything else connected.
Use USB OSX pendrive with LED link to assure USB activity; USB mouse serves normally.
If works, start to connect perypheral devices, untill board doesn't start again.

 

[BCN_Techs]

Now i have it out of chasis. And back again to same problem. not turning. conected usb mouse and pen and it doesnt work. No light

 

[BCN_Techs]

THanks informaticos. Problem solved changing SMC.

 

[2informaticos]

Maybe was just bad solders under SMC.
I think this because board worked good before.
Didn't try to reball it?

 

[BCN_Techs]

Yes. I mean i reballed it, not changed.