HP la-h329p no power

[dclass-pro]

Hi guys, I have this notebook that does not turn on. HP la-h329p
When I connect the power supply the white light does not turn on but it does not generate the 3v and 5v.
I find the voltage in the P2 pin so the first 3 mosfets are working, I also changed the charger and the problem persists.
On the battery connector I have about 2.8V on +BATT but on SDA and SCL I have 0V.
I checked and the 3v and 5v coils are not shorted to ground.
What can I try?

[mon2]

Link to the schematic? Do not post the actual schematic here but inside the dedicated schematic forum only. Share the links to the schematic if available.

The SDA / SCL may be 0v due to the missing 3v always on rail which will only be present if the main power rail is operational through the DCin mosfets.

Remove all power. Disconnect the battery as well. Measure the resistance to ground of the same SDA / SCL lines. If the resistance is low, then the TVS diode (usually SOT23-3 package) is defective and must be removed off the board to permit the SMBUS lines to operate normally.

Which charger IC is onboard? BQ series? Check the voltage to ground of:

REGN
VCC
ACDRV ; must be ~25v is all is well
ACN
ACP
CMSRC

Often, the fault in your case will be in the first 2 DCin mosfets since 3v and 5v rails are missing.

[dclass-pro]

I didn't understand in which section I have to put the diagram, can I have the link?
for the charger it mounts the BQ24735R, between the SDA/SCL lines and ground I have about 600K so it seems ok...
here are the values measured with the charger connected:
REGN - 5.9V
VCC - 19V
ACDRV - 25.6V
ACN - 19.3
ACP - 19.3
CMSRC - 19.3V

[mon2]

Sure, post here:

https://www.badcaps.net/forum/troubl...-requests-only

NB: The schematic may already be there but not sure on the silk screening on your board. Safe to post for now and share your link.

The voltages look good for this charger IC. If the 3v / 5v are absent, check the EN pins = enable pins for the same rails. Also check if the LDO rails are present or not.

Sometimes the EN pins are built up using 2 x resistors as a voltage divider that is feeding off the 19v main power rail and is a lower safe voltage to enable these always_on power rails. Inspect the resistance of each of the LDO and switching power rails (will have the inductor inline). If there are no shorts AND the enables are logic '1' then the regulator should function or is defective.

Alternate enables are created by the EC (external controller) that is usually a 8051 / ARM derivative. Assuming no liquid damage? Using the proper and suitable power adapter?

Being an HP, an analog voltage is used to gauge the power rating of the adapter - be sure you are not using a lab power supply unless this extra analog voltage is present. Only then can the EC properly gauge the power rating of your power supply. Dell uses the 1-wire communication for the same function but HP uses an analog voltage which is sampled by an analog to digital converter.

[dclass-pro]

https://www.badcaps.net/forum/troubl...21312-la-h329p

[dclass-pro]

checking on the diagram I have on the 2 ICs of the 5v and the 3v only the ENLDO_3V5V of about 4.3V but I am missing the 3VL which perhaps must be generated by the charger, but it is not generated by pin 5 ACOK.

[mcplslg123]

Wrong. ACOK is released by charging IC via a pullup resistor which in turn is powered by 3VL(LDO). This 3VL is generated by your 3V pwm ic.
If ENLDO & VIN is present on 3V regulator, it should release 3V LDO.
Since 3V LDI is missing, measure resistance to GND on 3V LDO(without any power source connected).
ACOK will remain low if 3V LDO is absent.

[dclass-pro]

Hi guys, sorry for my absence... I discovered the problem.
The +3V_LID line was shorted and unfortunately it comes from the processor.
I'm sorry but it's not repairable, thanks to all guys, see you next time

[mon2]

Sorry, unable to follow this conclusion albeit it is very early here.

+3V_LID is created by +3VL after it passes through the diode @ DC1. Can you confirm the voltage to ground of +3VL?

+3VL = +3VLP and is created by the internal LDO inside of PU301 (pin # 17).

This LDO rail will enable only if there is a valid voltage on the EN2 pin # 11 of PU301.

Check each of the above points of interest.

[dclass-pro]

I noticed that DC1 was heating up a lot and so I checked on pin 1 of DC1 and between pin 1 and ground I have a short so 0ohm.
I tried to inject 3v on pin 1 of DC1 and I noticed that it heats up the processor, so it is the one that is shorted

[mcplslg123]

RTC section of PCH is shorted-Precise answer to your fault. Quite a common phenomenon