820-3476 no power

[Kyle93]

This arrived with no power and no liquid damage. Board looks pristine. Not sure what to check next.

PM_BATLOW_L 3.3V

SMC_ADAPTER_EN 3.3V

PM_PWRBTN_L 3.4V

PM_RSMRST_L 3.3V

SMC_PM_G2_EN. - 3.43V

RTC_RESET_L. - 3.3V

PPVRTC_G3H - 3.43V

PCH_SRTCRST_L 3.36V

ALL_SYS_PWRGD 0V

 

[2informaticos]

Do you get 3V3_S5/SUS?

 

[Kyle93]

Yes 3.4v on 3V3_S5 and SUS

 

[2informaticos]

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L, at same time.

 

[Kyle93]

Yes, PM_PWRBTN_L has a drop pulse

 

[2informaticos]

Check PM_SLP_S4/3_L for pulse (at same time).

 

[Kyle93]

yes both PM_SLP_S4/3_L pulse

 

[2informaticos]

Check for pulse at all big cois; at same time when trigger SMC_ONOFF_L.
Do the same for ALL_SYS_PWRGD too.

Just in case, try to start in SMC bypass mode.

 

[Kyle93]

back to this board

yes all big coils and ALL_SYSPWRGD has a quick pulse when triggering SMC_ONOFF_L

 

[2informaticos]

Can you catch a pulse at PLT_RESET_L too?

 

[Kyle93]

No pulse at PLT_RESET_L

 

[2informaticos]

Check for pulse at pins 5, 6 & 3 of U1950.

 

[Kyle93]

pulse at pin 5 but no pulse at pin 6 & 3

 

[2informaticos]

Tie together pins 5 & 6 and test again the board.

 

[Kyle93]

Still no power but there is a pulse at pins 6 and 3 now

 

[2informaticos]

PLT_RESET_L pulsing now?

Try to start in SMC bypass mode.

 

[Kyle93]

All testing was performed with fan disconnected. When the fan is connected board now consistently powers up but fan spins very fast. Same with or without keyboard connected. only drawing .168 amps

 

[2informaticos]

If trackpad is not connected, the fan will spin with max speed.
Do you get CPU core voltage now?

 

[Kyle93]

CPU voltages still the same as before.

Without fan plugged in board only draws 0.76 amps but as soon as the fan is plugged in it goes up to 0.170 amps so still not fully booting.

 

[2informaticos]

As I said, fan spins to max, if trackpad is not connected; or has a problem with its temp sensors.
Keyboard is not involved here.

PLT_RESET_L stays high now?