820-4924 water damage PP5V rail pulsing

yair37

Member
water damage at u8020 area and u5870 area(was replace both) no other seeing damage.
charger green/orange, no fan
PPBUS-12V
PP5V rail pulse from 0-3v constantly.
 

2informaticos

Administrator
Staff member
"PPBUS-12V"
You have more than 2 years on the forum; didn't learn yet the importance of exact voltage???
Check it w/ and w/o battery connected.
Be sure to use original Magsafe 2 60/85W charger.

CPU coils pulse too?
What about PLT_RESET_L?
Try starting in SMC bypass mode.

I recommend you to reball SMC...
 

yair37

Member
PPBUS_G3H = 12.58
PP3V42_G3H = 3.4V
PPVRTC_G3H = 3.3V
PP5V_S5 = 5V
PM_SLP_S5_L 0V
SMC_ADAPTER_EN - 3.3V
PM_BATLOW_L - 3.3V trigger working.
PM_SLP_SUS_L - 0V
3V3_SUS - 0V
PM_RSMRST_L = 0V
PM_DSW_PWRGD - 0v
PCH_DSWVRMEN- 3.2v

dont bypass SMC
 

2informaticos

Administrator
Staff member
"PM_BATLOW_L - 3.3V trigger working."
I'm not sure what do you mean here; it MUST be steady high.

"PM_SLP_SUS_L - 0V"
Check PCH's RTC signals.
 

yair37

Member
update:
after replace SMC:
3V3_SUS 3.3V
PM_SLP_SUS_L 3.3V
PM_DSW_PWRGD 3.4V
PM_RSMRST_L 3.3V
PM_SLP_S5_L 0V

PM_BATLOW_L - 3.3V when i trigger SMC_ON/OFF_L its down to 0v and back to 3.3v

still SMC bypass not working..
fan not spin
 

2informaticos

Administrator
Staff member
Do the same for PM_SLP_S3L.
If pulse, then big coils should pulse too.
Also check ALL_SYS_PWRGD and PLT_RESET_L (for pulse).
 

2informaticos

Administrator
Staff member
Check all SPI Bus Series Termination resistors and traces.
Be sure no corrosion under U1950 and/or U6100/01, J6100.

Check for pulse on output voltages from page 63.
If no pulse, check for short, or lower than normal resistance to ground.
 
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