820-00165-a

[Mamdouh]

This board normally takes 0.8 watts but sometimes when it takes 3.5 watts spi_clk goes through 0.4 to 1 volt and repeats all resistors on that line are good and tried clean me bios no change.

 

[Mamdouh]

This only happens sometimes so it can be considered no power but this board was in pretty bad shape to begin with

 

[2informaticos]

You didn't post any basic signal/voltage...

 

[Mamdouh]

sorry about that.

Green light present
PPBUS_g3h - 8.6
pp3v42 - 3.42
pp5v_s5 - 5
pp3v3_s5 - 3.3
pp3v3_sus, ppvrtc - 3.3
pm_slp_s4_l is missing, i get 32khz on clock chip and dew_pwrgd is 3.4v
bios area had a bad resistor (r6121) replaced. All traces are good tried clean ME bios.
pp15v_tbt line was in bad shape not too sure what that does though

 

[2informaticos]

"pm_slp_s4_l is missing"
Why did you touch BIOS then???
You cannot suspect BIOS, untill power on sequence is completed...

Post PM_BATLOW_L, PM_PWRBTN_L, PM_RSMRST_L, PCH_DSWVRMEN, SMC_ONOFF_L and all PCH's RTC signals (4).
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.
Be sure to use original Magsafe 2 charger.

 

[Mamdouh]

PM_BATLOW_L - 3.3
PM_PWRBTN_L - 3.3 goes down to 0.35 when r5115 pads are touched
PM_RSMRESET_L - 3.3
PCH_DSWVRMEN - 3.2
SMC_ONOFF_L - 3.4

RTC_RESET_L - 3.3
PCH_INTVRMEN - 3.2
PCH_INTRUDER_L - 3
PCH_SRTCRST_L - 3.3

 

[2informaticos]

"PM_PWRBTN_L - 3.3 goes down to 0.35 when r5115 pads are touched"
Check for pulse at all PM_SLP_Sx_L signals at same time.

 

[Mamdouh]

all pm_slp signals pulse to around 0.4v sometimes they go higher to around 1v
some like s5_l only goes to 0.1.

 

[2informaticos]

Then corresponding Sx voltages must pulse too.
Keep in mind, PM_SLP_S4_L enables S3 voltages, and PM_SLP_S3_L enables S0 voltages.

Also check for pulse at ALL_SYS_PWRGD.
Don't forget pages 57 & 58.

 

[Mamdouh]

ALL_SYS_PWRGD pulses to around 2.5v. pp5v_s0 pulsed as well. Am i looking for a short on those 2 pages?

 

[2informaticos]

Check for short at any voltage rail which don't have a pulse...

 

[Mamdouh]

So i would have to check all S0 rails because i get a pulse on all of them, but if all_sys_pwrgd pulses dosen't that mean all other S0 rails pulse. do i need to check every line outside of S0 lines? All lines on page 62 pulse excpet backlight i dont have a screen connected so that shouldnt pulse i assume.

 

[2informaticos]

VCORE requires ALL_SYS_PWRGD, so check for pulse at CPU coils.
There are some voltages which don't have a power good signal sent to ALL_SYS_PWRGD; especially on page 58.
Also check at PLT_RESET_L and CPU_VCCST_PWRGD.

 

[Mamdouh]

everything there pulses. pp3v3_s4 stays at 0.3v while pp3v3_s5 stays at 3.3v. s4 does pulse to 3.3 all other 3v3 lines pulse. everything on the s4 line looks clean should i look into that more or could it be something else

 

[2informaticos]

"everything there pulses"
Do you mean ALL signals I mentioned in my last post, are pulsing?
If yes, try full known working BIOS.