acer LA-B991p ,It turns off after 4 seconds

[kokono]

Here I want to explain to you about a problem of Acer Model LA-B991P motherboard.
All voltage rails have been checked. All are there. But the motherboard turns off after three or four seconds.
I measured these signals:
EC_RST > 3.3
PLT_RST > 0
SYSON >3.3
PCH_PWROK > 3.3
SUSP# >3.3
PCH_RSMRST# > 3.3
PM_SLP_S4 > 3.3
PM_SLP_S3 > it comes and goes quickly
PM_SLP_S5 > it comes and goes quickly

Please guide me to check more signals.

[kokono]

Re: acer LA-B991p ,It turns off after 4 seconds

Update :
SYS_PWROK > 3.3
H_CPUPWRGD > 0
EC_RTCRST# > 0
VR_ON > 1v

[mon2]

Re: acer LA-B991p ,It turns off after 4 seconds

EC_RTCRST# > 0

RTC is stuck in reset mode if this signal is a logic '0'.

[kokono]

Re: acer LA-B991p ,It turns off after 4 seconds

RTC is stuck in reset mode if this signal is a logic '0'.

Thx, What does it mean? And where could the problem be?

[kokono]

Re: acer LA-B991p ,It turns off after 4 seconds

Does anyone have any ideas?

[Sephir0th]

Re: acer LA-B991p ,It turns off after 4 seconds

Yeah, double-check the suspicious measurents. From my understanding EC_ RTCRST# can't be low if the board is at least partial working.

[mcplslg123]

Re: acer LA-B991p ,It turns off after 4 seconds

I beleive EC_RTCRST# will be low . Its connected with N channel Q52. If it is high ,then it will pull down RTCRST. So i think its a false alarm.

[kokono]

Re: acer LA-B991p ,It turns off after 4 seconds

Somethings else to measure ?