820-4924-A : no boot, amber light, no PP3V3_S0, no PP3V3_S3, no PP5V_S0, no S3, no S4, but I do have S5.

[stef4n]

Hello,
I have a 820-4924-A, on which liquid was probably spill. Charger's light stays amber. No boot.
I found similar thread there : https://boards.rossmanngroup.com/threads/820-4924-no-pp5v_so-s3-s4-rails.53764/

I already measured the below:
PPBUS_G3H: 12.66V (F7140, pin 1&2)
PP5V_S5: 5.06V
PP5V_S4: 0
PP5V_S3: 0
PP5V_S0: 0
PP3V42_G3H: 3.44V (C4850, pin1)
PPVRTS_G3H 3.36V
SMC_LID: 3.36v
PP3V3_S4: 3.36V but...no on U8000 (See below9

PM_DSW_PWRGD: 3.43v
PCH_DSWVRMEN: 3.25v
PM_BATLOW_L: 3.36v
PM_RSMRST_L: 3.34v
PM_PWRBTN_L: 3.3v
S5_PWRGD: measured on R8141, pin2: 3.41V

Regarding PP3V3_S5 , I do have 3.36V on pin 1 of C8000, and on the testpad close to the top left corner of C8092.
but I have no voltage at all on pins 2, 4, 6, 8 of U8000
I also have my PP3V3_S5 on pins 1 and 4 of U7870: 3.36V

U8000 Suspect?

Can't figure out if PP5VS3 is supposed to be created from S4 or directely from S5.

Thanks

 

[2informaticos]

Be sure to use original 60/85W Magsafe 2 charger.
This board doesn't turn on with 45W charger, if no good battery connected.

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L, at same time.
If detected, PM_SLP_S4_L should pulse at same time.

 

[stef4n]

Good evening 2informaticos,

I dont have any 45W charger. Besides, I always use 85W for 15" and 60W for 13", and always the same chargers for all my mac.

Since this is only the second logic board I'm working on, I've never tried to trigger anything directly on a board so far;

SMC_ONOFF_L goes to U5110, but referring to the info available here : https://boards.rossmanngroup.com/threads/how-to-collection.60974/
I must solder a tiny wire on pin 1 of R5115, and then briefly touch the ground with the other side of the wire ? (Schematics, Page 39)

Simultaneously, I must use both hands to check pulse at PM_PWRBTN_L, without any oscilloscope.

What are we looking for there ? A defective keyboards/power button ?

I will update this post as soon as I can provide answers regarding SMC_ONOFF_L, PM_PWRBTN_L and PM_SLP_S4_L

Thank you for your help. Very much appreciated.

 

[2informaticos]

The reaction of mentioned signals will give us information about SMC and PCH state.
You don't need an o-scope to see if a signal drops 3-0V, or pulses from 0V to 2-3V.