Acer FH5AT LA-K093P Rev 1.0 missing +1.8v_EN

[champunk]

Hi, please help me out..
my laptop turn on 3secs then off. No post, fan no spin.
i have checked:
5valw OK
3valw OK
but not 1.8v
signal EN from EC to IC PU1801 is missing (0v).
PR1807 ok. Pin 20 EC = 0V.
Really hope someone can guide me further...
thanks

[ronelex]

Same issue to the unit I am Working Right now

[mon2]

Confirm the power rails of the EC. Is the EC being powered?

Check the clock of the EC. Is this EC being clocked?

Meter in diode mode. Remove all power. Red meter probe to ground. Black meter probe to tie missing EN signal. What is the diode mode measurement?

[ronelex]

Confirm the power rails of the EC. Is the EC being powered?

Check the clock of the EC. Is this EC being clocked?

Meter in diode mode. Remove all power. Red meter probe to ground. Black meter probe to tie missing EN signal. What is the diode mode measurement?

+3VLP_EC - 3.3v
+VTT_EC - 0v after power on 1v
+1.8VALW_ESPI - 0v after power on 0.2v
EC_RST# - 3.3v
EC_1.8V_EN - 0v
PCH_PWROK - 0v
PBTN_OUT# - 0v after power on 3.3v
SLP_SUS# - 0v
AC_IN - 3.3v
EC_ON -3.3v
ON/OFFBTN# - 3.3v
LID_SW# - 3.2v
MAINPWON - 3.3v
EC_RSMRST# - 0v
SYSON - 0v
VR_ON - 0v
PCH_DPWROK - 0v after power on 3.3v

PM_SLP_S4# - 0v on the first probe I manage to turn on the unit it measures 3.3v but after I turn it off no response again here

PM_SLP_S3# - 0v

What clock do I need to check, is it the 32khz clock sir??

[champunk]

+3VLP_EC - 3.3v
+VTT_EC - 0v after power on 1v
+1.8VALW_ESPI - 0v after power on 0.2v
EC_RST# - 3.3v
EC_1.8V_EN - 0v
PCH_PWROK - 0v
PBTN_OUT# - 0v after power on 3.3v
SLP_SUS# - 0v
AC_IN - 3.3v
EC_ON -3.3v
ON/OFFBTN# - 3.3v
LID_SW# - 3.2v
MAINPWON - 3.3v
EC_RSMRST# - 0v
SYSON - 0v
VR_ON - 0v
PCH_DPWROK - 0v after power on 3.3v

PM_SLP_S4# - 0v on the first probe I manage to turn on the unit it measures 3.3v but after I turn it off no response again here

PM_SLP_S3# - 0v

What clock do I need to check, is it the 32khz clock sir??

well, i finally found the problem.
Capacitor C22 shorted.
SOC_RTCRST# should 3V.