820-3478 Only first LED

[No-Clean]

Clean board client states that it just stopped working.

With bench PS sometimes the LED 2 and 3 come on and board seems to start up, but more often than not only first LED comes on.

Already tried a donor ISL6238 and same behavior.

Following the power rail list from page 100 board makes it all the way to S5 state

PP3V3_G3
PP12V_ACDC
PP12V_G3H
PP3V42_G3H
PP12V_S5
PP5V_S5
PP3V3_S5
All above rails present and correct

PP5V_S4 0V not shorted

 

[2informaticos]

Trigger SMC_ONOFF_L and check for pulse at PM_SLP_S4/3_L (at same time).

 

[No-Clean]

No pulse on either one.

 

[2informaticos]

Do you note drop pulse at PM_PWRBTN_L at least?

 

[No-Clean]

I do get a pulse on PM_PWRBTN_L when I trigger SMC_ONOFF_L, but not on PM_SLP_S4/3_L I tested again

 

[2informaticos]

PM_RSMRST_L stays high all the time?

 

[No-Clean]

If you mean PM_RSMRST_PCH_L_R or PM_RSMRST_PCH_L then yes.

 

[2informaticos]

Then should be something PCH related.
Check PM_DSW_PWRGD, PCH_DSWVRMEN and RTC signals.

 

[No-Clean]

PM_DSW_PWRGD 3.3V
PCH_DSWVRMEN 2.5V

RTC_RESET_L 3.3V
PCH_SRTCRST_L 3.2V
PCH_INTRUDER_L 3.1V
PCH_INTVRMEN 3V

 

[2informaticos]

Check if R1215 has correct value.

 

[No-Clean]

I measured it of circuit and it is correct at 386k~

 

[2informaticos]

Force the signal, with 47-100K, instead of 390K.

 

[No-Clean]

I put a 47k resistor PCH_INTVRMEN is still 3V and board still only has 1st LED turning on.

 

[2informaticos]

Should be PCH internal issue then...