Lenovo Ideapad 3 15IML05 MB : GS452/GS552/GS752 NM-C781 not trigger

[kamel]

Hi Ideapad when Plugged in 3.3vALW and 5vALW are on, but 1.05vALW and 1.8vALW absent. Power led lights and remains always on and laptop not trigger..
Found a burned spot on LV5075B IC, replaced with a new imported IC, but 1.05vALW and 1.8vALW still failing. .
EC IT8586E working voltages and signals are all ok except PBTN_OUT# 2.44V not changing when power button is pushed and EC_RSMRST# always 0.1V ??
Reflashed EC IT8586E and Main bios with newly download dump from Lenovo site to no avail.
Should I fix again a new L5075B and replace IT8586E to solve the issues.
Thanks for any suggestion.

[kamel]

Still waiting for your suggestion to help fix the issues. Thanks.

[mon2]

I see an EC bios dump in my database. Have you reflashed the EC bios? Always backup the original (twice & verify the filesize against the density of the device) before erasing and reflashing with another.

https://www.badcaps.net/forum/troubl...-lcfc_nm-c781p

[mcplslg123]

What is the point of circling some points on the pdf file without specifying what voltage is present or absent there?

Its wiser to mention all the enables/inputs along with outputs of this IC. this IC is a combination of multiple ic-so the info should be very detailed.

If anything is missing, its standard practice to check resistance to GND on that rail.

Overall, not much info to help you out.

[kamel]

[QUOTE=mon2;n3620072]I see an EC bios dump in my database. Have you reflashed the EC bios? Always backup the original (twice & verify the filesize against the density of the device) before erasing and reflashing with another.

https://www.badcaps.net/forum/troubl...-lcfc_nm-c781p[/QUOTErevert

Thanks for your reply.
Yes as mentioned above, I did reflash Ec and Main Bios with a dump from Lenovo support to no avail. Will try the bin you posted and revert.

[kamel]

What is the point of circling some points on the pdf file without specifying what voltage is present or absent there?

Its wiser to mention all the enables/inputs along with outputs of this IC. this IC is a combination of multiple ic-so the info should be very detailed..

The check points I circled are necessary for issuing 1.05vALW and 1.8vALW which should be present when adapter is plugged in (S4-S5 state). As the issue is "not triggering", the other voltages are not concerned at this stage. I attach new photo of LV5075B with voltages and signals measured before powering laptop.

If anything is missing, its standard practice to check resistance to GND on that rail.

Of course I did check resistance to gnd of failing outputs, no issue found.

+3VALW,+5VALW and 3VALW_PCH are present and my concern is why 1.8VALW and 1.05VALW are not outputted though all the conditions for their issue are present and LV5075B was replaced with a new imported one ? Should I suspect the new IC to be manufacturing defected ?

Any new suggestion is welcome.

[mcplslg123]

Both +1.8V and +1.05V rails are enabled by PCH_PWR_EN which in turn is issued by SIO. It should be 3.3V and not 2.4-2.5V

Measure PCH_PWR_En on SIO pin-is it 2.4V there? If yes, remove PR506/507 one by one to see if it rises to 3.3V.

[kamel]

[QUOTE=kamel;n3620806]

I see an EC bios dump in my database. Have you reflashed the EC bios? Always backup the original (twice & verify the filesize against the density of the device) before erasing and reflashing with another.

https://www.badcaps.net/forum/troubl...-lcfc_nm-c781p[/QUOTErevert

Thanks for your reply.
Yes as mentioned above, I did reflash Ec and Main Bios with a dump from Lenovo support to no avail. Will try the bin you posted and revert.

Flashed EC with the .bin file you posted didn't help triggering. found particularly pch_pwr_en = 0V. ?? So I Reflashed Back Ec with Lenovo support dump and got pch_pwr_en = 2.44V