ACER 5740 does not turn on

[anandvsalunke]

Hey guys,

ACER 5740 (motherboard JV50-CP MB 09285-1M) does not turn on and no display.

When power button is pressed, power leds turn on, exactly after 1 second, they turn off.

I checked all voltages and they seem fine, when power button is pressed. PLTRST is also fine.

Exactly after one second from turn on, it looks that SLP_S3# and SLP_S4# are turned off by PCH causing system off. All powergood signal is OK.

I have downloaded BIOS from ACER website and flashed, but the set still does not turn on. I have also reflowed the PCH HM55, but no luck.

At this point, I guess that I have bad PCH/ CPU.

Can anyone help me to troubleshoot, i would appreciate that before i go for PCH/ CPU change.

[anandvsalunke]

Anyone? Any guess? I am going ahead with HM55 replacement. Hope this solves the issue. Wish me luck..

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[deepak9812423104]

3v n 5v coming or not,,,,in controler powerbutton on and downbutton droup or not.....

[anandvsalunke]

I told PLTRST is OK, of course all voltages are OK, and signal to pch on power button press is OK. But it powes off exactly after 1 second.
Another interesting observation is that the RSMRST to PCH is missing. Upon further investigation, I find the pull up resistor to RSMRST and diode in series were missing. I added those, but still SIO is not sending RSMRST to PCH upon power button press.
Can anybody confirm that RSMRST goes high upon power button press on this board?

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