Lenovo Yoga 12 cannot turn on...please help

[sparrow2719]

Hi, I have lenovo yoga 12 motherboard code: ZIPS3 LA-A342P cannot turn on. Pressing the power button I have +3VALW and +5VALW but no display, no fan spinning etc, completely quiet with current comsumption about only 0.6A.

I have tried reflashed the EC KB9022 but still the same, reflashed the BIOS just the same.

Tracked the power distribution and found out NO +3VM (BIOS) and NO +3VS, the voltage measured in on pic 1.jpg.

Further track and found out there is 0V on SUSP# signal on EC,so there is no +3VS and +5VS (pic 2.jpg).

is this sign of bad ec ?
or do I have to look at something else I missing ?

[mcplslg123]

Re: Lenovo Yoga 12 cannot turn on...please help

Do you have RSMRST# at kbc??

[sparrow2719]

Re: Lenovo Yoga 12 cannot turn on...please help

Do you have RSMRST# at kbc??

EC_RSMRST# is 0V

[jasko_jacker]

Re: Lenovo Yoga 12 cannot turn on...please help

U3601 Is ok ?
Susp# EC should drive on1 and on2 check this line

[sparrow2719]

Re: Lenovo Yoga 12 cannot turn on...please help

U3601 Is ok ?
Susp# EC should drive on1 and on2 check this line

U3201 is ok, I injecting 3.3V on the SUSP# line and U3201 is active, +5VSLOAD, +5VS, +3VSLOAD, +3VS is immediately available.


But still no EC_RSMRST#, no SUSP# signal from EC.

[jasko_jacker]

Re: Lenovo Yoga 12 cannot turn on...please help

U3201 is ok, I injecting 3.3V on the SUSP# line and U3201 is active, +5VSLOAD, +5VS, +3VSLOAD, +3VS is immediately available.


But still no EC_RSMRST#, no SUSP# signal from EC.

We should check susp# line , post schematic.

[sparrow2719]

Re: Lenovo Yoga 12 cannot turn on...please help

We should check susp# line , post schematic.

Here it is:

[Simon Leung]

Re: Lenovo Yoga 12 cannot turn on...please help

Thank you all members in this column to share your issues and advices for Lenovo Yoga 12 issues even though the posts are few years ago and is helpful to me .

I am Simon Leung and just have joined this forum and looking for info of this laptop MB power circuit issues . The posted schematic help me trouble shooting my old laptop pc. .