Hello everyone, this is my first post. Unfortunately I don't speak russian, so I have to write in english instead.

I'm repairing a dead laptop Hp DV5 model 1215ca with the following symptom : doesn't power up with either battery or AC. Only AC connector lights when adapter is plugged in.
I found the following voltages on KB3926QF 00 : ACIN : 3.4V-LID_EC#:3.8V-EC RST : 3.77V-NBSWON# : 3.8V-
S5_ON : 0V ?? before and after pressing power button, must be around 3.8V-DNBSWON# : 0.3V ??? before and after pressing power button instead of 3.8V-RSMRST# 0V that seems to be correct as checked on a DV6 working laptop (almost similar to DV5).

I guess finding DNBSWON# 0V is a consequence of S5_ON= 0V, which comes out of EC, and supplies 3V_S5 to DNBSWON#

Do I have to replace the EC kb3926 or is there any other steps to be taken before that (any other voltage measure or signal to check with oscilloscope) ??

Should appreciate any help.

Thanks

before replace flash bios firmware (save old)
laptop platform?

Doc_66, I appreciate your quick reply, and sorry for my late response to your suggestion.
Before trying to flash bios, I would like to precise that mobo is intel based and that
Bios Mem Cs pin=0.3V only, instead of 1.8V in a working DV5. that might confirm bios problem, but but Mem Cs signal measured with oscilloscope gives a wave form, and that's a normal signal.
The main problem is that DNBSWON# issued from EC to southbridge is always 0.3V instead of 3.8V, before and after pressing power button.
In DV5 schematic DNBSWON# is supplied with +3VS5, and EC S5_ON is needed to issue +3VS5. I found EC S5_ON=0V instead of 3.8V, unchanged before and after pressing power button. that's why I'm rather suspecting ENE KB3926 fail.
Any new idea or comment will help.