820-00165 - A1466 MacBook Air

[ronaldo]

Hi, here I have this Mac with Green and Orange light, but no power.
Has no signs of liquid.
Q7560 replaced as it was blown.
After a few checks, I found that PM_SLP_S4_L is missing.
I replaced
clock chip U1900 and Y1915 just to make sure it was OK.
Still no power.

I removed R8111 and PM_SLP_S4_L is up - 3.3V.
I solder R8111, the line goes.

Furthermore, I read that it may be a dead CPU.
I Just wonder if anyone has a better idea of what is happening here, please.

 

[2informaticos]

Check diode mode to ground at L7430.

Do you get steady L7520 voltage, when R8111 is removed?

 

[ronaldo]

L7520 5.43V steady when R8111 removed
L7430 0.269 diode mode

 

[2informaticos]

Resolder R8111.
Remove R8168 and check if L7430 voltage appears.

 

[ronaldo]

After resolder R8111 and remove R8168 voltage on L7430 cycle 2 time for less than a sec and stays on 0V

 

[2informaticos]

Test changing U7400.
May need to change Q7430 too.

 

[ronaldo]

Both replaced and still no fan spinning.

 

[2informaticos]

Remove R8178 and check again L7430 voltage.
Keep in place R8111.

 

[ronaldo]

After remove the R8179 the voltage on L7420 is 1.20V.

 

[2informaticos]

Do you mean R8178?
Board stays on, with CPU core voltage present?
Did you test USB activity?

 

[ronaldo]

Yes, I mean R8178.
CPU core voltage not present.
USB has power, but no activity.

 

[2informaticos]

Post U1950 voltages.

 

[ronaldo]

With and without R8178, the voltages are.
ALL_SYS_PWRGD - 0V
CPUVR_PGOOD_R - 0.05V
SYS_PWROK_R - 0V
PM_S0_PGOOD - 0V
SMC_DELAYED_PWRGD - 0V
PP3V42_G3H - 3.41V

 

[2informaticos]

So you have steady 1.2V at L7420, but ALL_SYS_PWRGD stays low?

 

[ronaldo]

yes

 

[2informaticos]

I realized we talk about L7439 in fact.
So board stays in S3, but fails to pass into S0.
Resolder R8178 for next tests.

Seems that your board is in the "cycling two tines", the worst scenario.
L7310/20 and PLT_RESET_L pulsing too?

 

[ronaldo]

L7310/20 and PLT_RESET_L pulsing too

 

[2informaticos]

Test if simething change in SMC bypass mode.

Very likely PCH problem.
Check all voltages from page 11.
If all present, try heating PCH/CPU with quality flux.
I recently solved same problem caused by accumulated crap underneath.

 

[ronaldo]

On SMC bypass mode, fan cycles twice and stop.
PP3V3_S5 - 3.3V
PP3V3_SUS - 3.3V
PP3V3_S0 - 0.10V (Cycle to 3.3V for a sec if press power button)
PP1V05_S0 - 0V (Cycle to 0.99V for a sec if press power button)

 

[2informaticos]

"Check all voltages from page 11."
There are several series coils and 0 ohm resistors; don't you want to check all them???