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820-4924 - Wont Power On

N

netjordan

New member
Hello,

We have a 820-4924 that won't power on, they have reported water damage, however board generally looks in good condition except a small amount of corrosion arround C8301.

MagSafe light is going orange, and i've performed an SMC reset, it goes green then back to orange fine.

PPBUS_G3H - 12.58v
PP3V42_G3H - 3.41v
PP5V_S5 - 5.02v
PP5V_S0 - 0v
PP3V3_S5 - 3.34v
PP3V3_S4 - 0v
PP3V3_S3 - 0.282v
SMC_ADAPTER_EN - 3.38v
SYS_PWR_OK_R = 0v
PLT_RESET_L = 0v

SMC_CLK32K = 32khz

Can you advise on the next steps?

Thanks,
Jordan
 
2informaticos

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Are you using original 60/85W Magsafe 2 charger?
Do you get 3V3_SUS?

Post PM_BATLOW_L, PM_DSW_PWRGD, PCH_DSWVRMEN.
 
N

netjordan

New member
Hello,

Yes, I am using orginal apple 85W charger.

PP3V3_SUS - 3.34v
PM_BATLOW_L - 3.34v
PM_DSW_PWRGD - 3.41v
PCH_DSWVRMEN - 3.24v

Thanks,
Jordan
 
2informaticos

2informaticos

Administrator
Staff member
Now post PM_PWRBTN_L, PM_RSMRST_L, SMC_ONOFF_L.
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L, at the same time.
If present, check for pulse at all PM_SLP_Sx_L signals.

Use R5115/16 pads, instead of power button.
 
N

netjordan

New member
PM_PWRBTN_L - 3.4v
PM_RSMRST_L - 3.31v
SMC_ONOFF_L - 3.41v

When pulling down SMC_ONOFF_L, PM_PWRBTN_L goes LOW

PM_SLP_S0_L - 0v - no pulse
PM_SLP_S3_L - 0v - no pulse
PM_SLP_S4_L - 0v - no pulse
PM_SLP_S5_L - 0v - no pulse
 
2informaticos

2informaticos

Administrator
Staff member
The problem is then on PCH side.
ONLY if you are really sure no pulse at all, when SMC_ONOFF_L is released.
Check the 4 (four) PCH's RTC signals from page 12.
 
N

netjordan

New member
Double checked all of the PM_SLC_Sx_L, checked with trigger on scope

PCH_INTRUDER_L, PCH_INTVRMEN, PCH_SRTCRST_L and RTC_RESET_L are all present.
 
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