820 4924 (2015), don't turn ON

[Noguinfor]

Hey guys,

Working on 820 4924, No signals off water damage and corrusion components. (i'm the first to open this mac).

PPBUS_G3H = 12.58
PP3V42_G3H = 3.4V
PPVRTC_G3H = 3.3V
PP5V_S5 = 5V
PP5V_S4 = 0V Diode mode = 0.530v
PP5V_S3 = 0V Diode mode = 0.378v
PP5V_S0 = 0V Diode mode = 0.390v

SMC_ADAPTER_EN - 3.3V
PM_BATLOW_L - 3.3V
PM_SLP_SUS_L - 3.3V
3V3_SUS - 3.3V
PM_RSMRST_L = 3.3V

PCH_CLK32K_RTCX1 = 0.4V tested with osclloscope and i have wave and 32.khz
RTC_RESET_L = 3,3V
PPVRTC_G3H = 3.3V


already test with original charger 85W.
when i plug the battery and test with power supply I have normal consumption 1.3A because only charge the battery!! No component heating too!!

any suggestion??
thanks

 

[2informaticos]

First suggestion is stop to check S0 voltage, when you already detected missing S3 one.
Same as missing S4 voltage, no need to look for S3 one.

"RTC_RESET_L = 3,3V"
There are 3 other important signals, in the same page 12.
Next, check PCH_DSWVRMEN and PM_DSW_PWRGD on page 13.

Also need to confirm drop pulse at PM_PWRBTN_L every time SMC_ONOFF_L is triggered.
You should get one pulse at PM_SLP_S4_L in the same moment; valid for S3 too.

 

[Noguinfor]

Ty for your advice !!

PCH_DSWVRMEN = 2.45V
PM_DSW_PWRGD = 3.4V

yes when i triger smc_on_off i confirm a drop pulse!

PM_SLP_S4_L and PM_SLP_S3_L i check a high pulse!!

 

[2informaticos]

Check now if all S3/S0 voltage pulse too...

 

[Noguinfor]

i can see on pulse high on s3 and s0 lines when i plug the charge as also SMC_ONOFF_L is triggered.

 

[2informaticos]

Check for pulse at pins 7 & 3 of U1950 too.
Does it start in SMC bypass mode?

 

[Noguinfor]

i check a high pulse to at pin 7 and 3 of U1950|

already check for corrosion under scoop but this board are very clean!

Doesn't start with SMC bypass mode! =(

oyu have more ideas?? thanks

 

[2informaticos]

Check if all voltages from pages 61/63 try to appear too; at least pulsing.
You can also check there for short/low resistance to ground.

 

[Noguinfor]

hey ,

i have a 820 3476 board working. can i compare the values with each other ?? in your opinion better to measure on diode mode or resistance?? thanks

 

[2informaticos]

Always start in diode mode.
When you get very low value (i.e. less than .010), then switch to ohm mode.