820-4924-A no PP5V_S3

Hello

Little corrosion around smc, cleaned and reflowed.

GREEN LIGHT: OK
PPBUS_G3H_R: 12.8V
SMC_ONOFF_L:3V
PP3V3_S5: 3.6V
P3V3S5_EN: 3.6V
PP5V_S3: 0V
P5VS3_EN: 0V
PM_SLP_S4_L: 0V

Any idea?
Thanks!
 

2informaticos

Administrator
Staff member
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).
If detected, check for pulse at PM_SLP_S4_L too.
 

2informaticos

Administrator
Staff member
Do you get 3V3_SUS?
What about PM_DSW_PWRGD, SMC_ADAPTER_EN, PCH_DSWVRMEN, PM_BATLOW_L and RTC signals?
 
PP3V3_SUS: 3.4V
PM_DSW_PWRGD: 3.6V
SMC_ADAPTER_EN: 3.6V
PCH_DSWVRMEN: 3.3V
PM_BATLOW_L: 560mV
RTC_RESET_L: 3.4V
PCH_SRTCRST_L: 3.4V
PCH_INTRUDER_L: 3.12V
PCH_INTVRMEN: 3.44
 
I reballed the SMC and same issue. Should I try with another one? (If so, could I use one from a 820-3476?)
 
Last edited:
I do not have a known good battery to test at the moment.

Customers battery seems to be charging but no power.

Tested with Original 85W and customers battery and no power.

SMC Bypass same problem.

Should I try ultrasonic cleaner? (Since I found some corrosion around SMC)
 
I replaced the SMC (from a 820-3476 ) and now I get the:

-PP5V_S3: 5V
-All big coils voltages (including CPU ones)
-PPVIN_S0SW_LCDBKLT: 0V
-TBTBST_BOOST: 0V
-the board takes 300mA
-power button responds
-no video

Do you think this can be an issue of the SMC no beign from the same model?
 

2informaticos

Administrator
Staff member
Did you test USB activity?

As now you've confirmed to have bad (original) SMC, find another from 4924 donor board.
 
I replaced the SMC for one of the same model board but same issue.

-No video on screen
-No external video
-Takes 800mA
-CPU gets hot
-Tried other BIOS (from the donor board) and same
-No USB activity detected.

Any idea?
 

2informaticos

Administrator
Staff member
Check all SPI Bus Termination resistors and theyr traces.
PLT_RESET_L comes high?

Try known good BIOS, should be posted on the forum.
 

2informaticos

Administrator
Staff member
"PLT_RESET_L comes high?"

Be sure traces between all SPI resistors are good.
Also check solders and traces of U6101.
Inspect J6100 for corrosion.
 
Top