820-00165 Macbook Air No Fan Spin

[Instafixx]

Customer says it is repaired before but i couldnt find any traces of any work done. No Corossion as well.

PPBUS is 8.58V
PP3v42 present.

I noticed that U8020 is a but chipped off from the corner but all voltages are stable.

U8040 also same . Chipped Off. But here all Voltages are zero. (Checking Bare Board on Bench.)

 

[2informaticos]

"here all Voltages are zero"
Where exactly?

Check Q6060 voltages and diode mode readings.
Compare with good board.
Did you try known good fan?

 

[Instafixx]

U8040 Voltages are 0V.
I may have mislead you. The problem is that machine doesnt turn on.

 

[2informaticos]

You've just said "no fan".
I supposed to have an working machine, just no fan spinning.

Do you get 3V3_S5/SUS?

 

[Instafixx]

Yes i do get it.

 

[2informaticos]

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).

 

[Instafixx]

Yes there is a drop in pulse

 

[2informaticos]

Then check for pulse at PM_SLP_S4_L, at same time.

 

[Instafixx]

Not pulsing

 

[2informaticos]

Looks like PCH issue.
Check PM_BATLOW_L, SMC_ADAPTER_EN, PM_DSW_PWRGD, PCH_DSWVRMEN and the 4 PCH's RTC signals.

Just in case, test SMC bypass...

 

[Instafixx]

All Signals gave 3.3V except PCH_INTRUDER_L is 3V.

No Success with SMC Bypass

 

[2informaticos]

Do you get 1V05_SUS?
ALso check PM_RSMRST_L.

 

[Instafixx]

yes. i get both. Stable

 

[2informaticos]

Heat PCH area with quality flux.
In case of accumulated crap underneath.

 

[Instafixx]

UPDATE - Spoke to the customer and the shop he got it repaired from somewhere. They had replaced U7701 a month back. But the i checked that area.It looked okay to me.

Should we go for PCH ?

 

[2informaticos]

Yeah...

 

[Instafixx]

Did that. No effect. not getting any voltage at L7520.

 

[2informaticos]

"check for pulse at PM_SLP_S4_L, at same time"
Did that again?

 

[Instafixx]

Yes. No Pulse here.

 

[2informaticos]

Bad PCH...