VR_ON, ICH_POK missing

[PinGuy]

Trying to get a Lenovo G450 to turn on. When pressing power, the power led goes on for about a second, then off. And it won't turn on anymore until power-cycled.
Measuring at the EC (page 36 at the schem), all these signals are at 0V, and blink to 3V for a brief moment when powering on:
SLP_S3, S4 & S5
SUSP#
EC_RSMRST
SYSON
EC_LID
EC_ON

VR_ON is always 0V
ICH_POK_EC is always 0V

What condition is needed for those 2 signals to go high?

[Techtiger]

Re: VR_ON, ICH_POK missing

For VR_ON (We are on ) H_PWRGOOD / ALLPWRGOOD / PWRGOOD for ICH_POK_EC +3VS voltage is required trace back ,Check the requirements of EC & Bios pins voltage? Flash bios backup original bin

[PinGuy]

Re: VR_ON, ICH_POK missing

Good info, techtiger, thank you.
3VALW is present, but when checking the mosfet that turns 3VALW into 3VS, I found that the SUSP signal is always at 3V, and it won't "flicker" to 0 when powering on, like #SUSP does (to 3V of course), when it arrives to Q37. So what can force SUSP to be always 3V? Maybe a short somewhere? I checked all coil outputs and there are no shorts to ground

[PinGuy]

Re: VR_ON, ICH_POK missing

Please correct me if I'm wrong, so when there is power but the system is off, SUSP is 1, and all the mosfets it controls are off, and when the power button is pressed, the EC sends a 1 through SUSP#, making SUSP 0 and hence making all the mosfets turn on so the computer starts? Is this how this works or am I getting it the other way round?

[Techtiger]

Re: VR_ON, ICH_POK missing

[QUOTE=PinGuy;1107532]Good info, techtiger, thank you.
3VALW is present, but when checking the mosfet that turns 3VALW into 3VS, I found that the SUSP signal is always at 3V, and it won't "flicker" to 0 when powering on, like #SUSP does (to 3V of course), when it arrives to Q37. So what can force SUSP to be always 3V? Maybe a short somewhere? I checked all coil outputs and there are no shorts to ground ]

Q37 is NPN transistor When pin 2 gets positive supply SUSP# from EC NPN gets ON and send a negative supply so R279 will stop sending voltage for pin2 of (r297) now vola!SUSP

[Techtiger]

Re: VR_ON, ICH_POK missing

Please correct me if I'm wrong, so when there is power but the system is off, SUSP is 1, and all the mosfets it controls are off, and when the power button is pressed, the EC sends a 1 through SUSP#, making SUSP 0 and hence making all the mosfets turn on so the computer starts? Is this how this works or am I getting it the other way round?

Not all the fets only +3/5 SUS +RAM_SUS

[PinGuy]

Re: VR_ON, ICH_POK missing

Q37 is NPN transistor When pin 2 gets positive supply SUSP# from EC NPN gets ON and send a negative supply so R279 will stop sending voltage for pin2 of (r297) now vola!SUSP

I tried clipping the collector of Q37 to ground but it will not even try to power up this way, not even a brief blink at the power led. I also tried clipping it right when pressing the power button, but the power led goes off right when I send SUSP to ground

[Techtiger]

Re: VR_ON, ICH_POK missing

You have to check EC pin 9 67 37 117 127 16 & Bios pin Voltage

[PinGuy]

Re: VR_ON, ICH_POK missing

9, 16, 37, 67 and BIOS VCC are 3V and go to 0V 2 seconds after power button is pressed. So for some reason +3VALW goes to 0 after powering on.
117 is at 0V and blinks to 3V for half a second when power is pressed.
127 is always at 3V (using the AC adapter)

[Techtiger]

Re: VR_ON, ICH_POK missing

9, 16, 37, 67 and BIOS VCC are 3V and go to 0V 2 seconds after power button is pressed. So for some reason +3VALW goes to 0 after powering on.
117 is at 0V and blinks to 3V for half a second when power is pressed.
127 is always at 3V (using the AC adapter)

can you test PL401 +3VALWP / PL402 +5VALWP if the voltage drops when pressing the PWRBTN & makes sure no short in RTCVCC section

[PinGuy]

Re: VR_ON, ICH_POK missing

Indeed, +3 and +5VALWP go to 0V after 2 seconds of pressing power.
The first thing I did when checking this one was replacing the old ML1220 battery (was at 1.8V) with a new CR2032, and removed PD104 to isolate the recharging circuit from the battery. CHGRTC is at 3.2V, RTCBATT is 3V.
Could it be that the EC it needs it to be 3.2V to power on?
Will try to check RTCVCC if I find it, as there is no silkscreen for the capacitors and resistors, and there's no board view. Thanks for the pointers!

[PinGuy]

Re: VR_ON, ICH_POK missing

I found R823 after tracing visually and confirmed RTCVCC is at 3V.