hp dv4 2160us cannot turn on

[String2016]

hi everyone i need help on this hp dv4 2160us the problem is when i check the charger original hp charger shows 19v but when i measure on dc jack shows only 15v and there is no light and cannot turn on if charger only plugged in but when battery can turn on but shuts of 5 seconds.if charger only plugged in there is no 3v on power button but when battery plugged in there is 3v on power button but the bios chip there is no 3.3v on pin 8 both charger and battery only plugged in. there is no 3.3v and 5v on the coil when i checked the first switch mofest there is 15v and also PL1 AND PL2 have 15v i checked resistance after first switch mostef no short to ground but the resistor 000 beeping to the ground.anyone please i need help on this. the Board code: NAL70 LA-4106P REV 1.0

[String2016]

Re: hp dv4 2160us cannot turn on

update: i slightly reflow pch laptop can turn on now but 5 secs shuts off and then turn again and shuts off every 5 seconds. can someone have a working bios for this model ill try to flash the bios please share

[String2016]

Re: hp dv4 2160us cannot turn on

laptop now can turn on but every 5 seconds shuts off i have attached the schematic and the bios chip is MXL3205DM and its an I5 processor with no dedicated graphics can someone share a working bios please

[piernov]

Re: hp dv4 2160us cannot turn on

If the PCH is HM55, I think it is bad. You'll have to replace it.

[String2016]

Re: hp dv4 2160us cannot turn on

yup pch is hm55 could this be bad?if there is a working bios for this model ill try first if still the same issue it could be bad pch can someone share first the working bios please

[piernov]

Re: hp dv4 2160us cannot turn on

I've seen multiple reports of HM55 going bad and I experienced it myself, so I guess its reliability starts to falter after a few years.
About the BIOS, search for "LA-4106P" on this forum, you should be able to find a couple of dumps.

[String2016]

Re: hp dv4 2160us cannot turn on

thanks piernov ill try first the bios flash if its failed then hm55 dead.because problem is laptop now can turn on but every 5secs shuts off and on

[String2016]

Re: hp dv4 2160us cannot turn on

already tried flashed the bios with i got here in this forum still the same issue turns on 5 seconds shuts off i think PCH is bad i think you are right piernov

[piernov]

Re: hp dv4 2160us cannot turn on

It could be something else, like a missing power rail, try to check them all, and if one is missing, check the input voltage and the enable signal of the DC-DC controller for this power rail.

[String2016]

Re: hp dv4 2160us cannot turn on

ill forgot to tell that i only flashed the main bios chip ill try the ec flashed again i already check 19v power rail all voltages present