820-3302 Not turning ON

[Bouba148]

Led501 ON

PP12V_G3H: 12.09V
PP3V42_G3H: 3.416V
PP12V_S5: 12.09V
PP5V_S5: 4.979V
PP3V3_S5: 3.294V

No S4 State when triggering the power button.
PM_SLP_S5_L not pulsing when trigger on SMC_ONOFF_L / PM_PWRBTN_L
PP3V3_G3H_SMC_VDDA: 3.416V

I'm suspecting the PSU but I don't have a spare one to test.....
I just wanted to make sure that the issue is not coming from the board itself before ordering a new PSU

 

[2informaticos]

Why PSU, if delivers 12V?

PM_PWRBTN_L reacts (drop pulse) triggering SMC_ONOFF_L?
Use J5020 pads, instead of external power button.
Don't forget to check RTC signals.
Remove CMOS coin cell, board should then start by itself.

 

[Bouba148]

Yes the PSU delivers 12V, but we only need 12V? , no other signal like SMC_ACDC_ID?

With the CMOS coin cell removed:
PP3V3_G3H_RTC: 3.295V
PM_PWRBTN_L reacts (drop from 3.404V to 0.340V) when triggering SMC_ONOFF_L by shorting C600

But still the board doesn't start ( fan not spinning )....

Also tried SMC bypass mode.....no effect except led is delayed

 

[aprendiz]

On these usually shorted USB, check that first.....

 

[Bouba148]

Checked all RX N/P TX N/P of all 4 usb ports none of them is shorted to Gnd

 

[aprendiz]

I mean 5V from USB

 

[Bouba148]

Sorry,

but none of the 4 PP5V_S4_EXT is shorted to gnd they all mesure around 0.500V in diode mode to gnd

 

[Bouba148]

but at L7650 Pin 2 (PP5V_S4) I'm mesuring 0.148V in diode mode

 

[2informaticos]

If PM_PWRBTN_L reacts, check for reaction at all PM_SLP_Sx_L signals at same time.

"Don't forget to check RTC signals."
Is OK you've checked RTC power, but I was talking about ALL (4) RTC signals...

 

[Bouba148]

RTC_RESET_L: 3.277V
PCH_CLK32K_RTCX1: 0.580V
PCH_CLK32K_RTCX2: 0.136V

PCH_CLK32K_RTCX2 is directely generated by U1800

 

[2informaticos]

Still missing 3 RTC signals...

 

[Bouba148]

here we go.......

RTC_RESET_L:3.291V
PCH_SRTCRST_L: 3.291V
PCH_INTRUDER_L: 2.880V
PCH_INTVRMEN: 3.162V

 

[2informaticos]

All good.

"If PM_PWRBTN_L reacts, check for reaction at all PM_SLP_Sx_L signals at same time."
Any comment???

 

[Bouba148]

When I short SMC_ONOFF_L to gnd, PM_PWRBTN_L react and drops to 0.3V but none of the PM_SLP_S5/4/3 reacts they just mesure 0V

dead u1800? or ,need a reflow?

 

[2informaticos]

What about PM_RSMRST_PCH_L?
If OK, then looks like bad PCH.
You can try a reflow, just in case crap accumulated underneath PCH.

 

[Bouba148]

PM_RSMRST_PCH_L is solid and mesuring 2.88V and never drops when I trigger SMC_ONOFF_L

 

[Bouba148]

Reflowed PCH same issue......dead PCH I guess