820-4924 green/orange light, not turning on.

tlough75

Member
I have an 820-4924 that came in as no power due to liquid damage. I found surface corrosion around U8330 and SMC. Stone dead with PPBUS at 12.23V. I found the trace for R5170 (SMC_RESET_L) was broken so I ran a jumper. I also ran a wire to R5173. I now have PPBUS at 12.59V, PP3V42 is 3.42V, etc. I checked all the power rails and found them up to PP5V_S4.
 

2informaticos

Administrator
Staff member
If you get into S4 state, power on sequence is started by PCH; as it released PM_SLP_S5_L signal.
Are you sure no PM_SLP_S4_L present?
Check for pulse at least, when you trigger SMC_ONOFF_L.
 

tlough75

Member
i think I am getting 2 little jumps on my multi-meter. I'll check with a scope later to confirm. The last digit on my DMM goes from 0 to 1 when I turn on power supply.
 

2informaticos

Administrator
Staff member
"I checked all the power rails and found them up to PP5V_S4."
Seems that I wrong understood you; I assumed it is present.
Be more explicit when you post...
 

2informaticos

Administrator
Staff member
Post the basic signals which we always mention for power sequence.
Use R5115/16 pads to trigger SMC_ONOFF_L, instead of power button.
Test with trackpad/KB disconnected, nor RIO flex.
 

tlough75

Member
3v3-sus: 3.3v
s5_pwrgd: 0v
pch_dswvrmen: 3.3v
pm_dsw_pwrgd: 3.42v
pm_rsmrst_l: 3.3v
pm_pwrbtn_l: 3.42v
pm_batlow_l: .036v
smc_onoff_l: 3.41v
 

2informaticos

Administrator
Staff member
"s5_pwrgd: 0v
--------------------
pm_dsw_pwrgd: 3.42v"
Can explain that???
Read the note at page 64.

"pm_batlow_l: .036v"
Are you using correct original 60/85W Magsafe 2 charger?
 

tlough75

Member
I do not see the note on page 64 you are talking about. and yes I am using original charger. I am not familiar with PM_BATLOW_L. The board is out of the chassis if that makes sense.
 

tlough75

Member
OHHHHH, I get it now. S5_PWRGD goes to the SMC then the SMC puts out PM_DSW_PWRGD. So you cannot really have PM_DSW_PWRGD without S5_PWRGD.
 

2informaticos

Administrator
Staff member
Check again the signals.
If possible, test the same signal in different points; this way can discard broken trace.
 

tlough75

Member
Ok, i will try that. I take it I am just looking for S5_PWRGD and not the others since they are present. Just want to make doubly sure.
 

tlough75

Member
Ironically enough, R5192 is the exact resistor I had to run a wire to... That resistor is for SMC_S5_PWRGD_VIN. That was one of the two spots with blown probe points.
 
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