AC adapter power is sucked from 19.9v to 0v?

[irfan-1]

Hiya my HP OMEN 15-DH1005NA not working so i opened it to check the voltage, when i check the ac adapter power i see 19.9v which looks fine but when i connect the battery to the motherboard the ac adapter power starts to lower down from 19.9v to all the way to 0v,
to get the ac adapter power back to 19.9v i need to unplug it for a few seconds and plug it back so it will work as 19.9v again,
anyone has any idea why this happens???

[mon2]

Does the laptop power up on if using only the power adapter? (Disconnect the battery)

[irfan-1]

No it doesn't i haven't able to fix the laptop yet

[mon2]

Share all silk screening on the logic board. Is there a schematic available? Link it but only inside of the dedicated schematic forum. Search for some marking like 'LA-****' or similar which may identify the logic board. Otherwise, the plan B is to hunt for the DCin mosfets and the local charger IC that is onboard. HP likes to use the 'BQ' series chargers from Texas Instruments so the DCin mosfets x 2 will most likely be the N-channel type.

Share pics of what you suspect to be the charger IC.

[irfan-1]

I have tried for a long time but can't find the schematic for the HP OMEN 15-DH1005NA,
i really don't have a clue how the charger IC looks like?

[irfan-1]

I have a feeling it's this one the one called PQB01

[mcplslg123]

PQB1 is a mosfet and not charging IC. Look nearby this mosfet or just on the opposite side of PQB1. The charging ic may be named BQXXXX/ISLXXXX etc. eg BQ24780/ISL9538

[irfan-1]

I will have a look, am sending you both side of the motherboard just in case you can point it out

[mcplslg123]

The Pics are not very clear but its very likely near the battery connector. just have a close look.

[irfan-1]

Hiya i just been busy the last few days, but i tried to look for the chip as you mentioned but i couldn't find it anywhere, i have tried taking closer and smaller pictures if you can have a look,

Thank you

[mon2]

See attached.

[MontyL]

My eyes!!! Whoever was waving a soldering iron around there hasn't done you any favors.

You seem to be missing PD2, and the resister just to the left of it appears to be misaligned and quite likely shorting something it shouldn't be. Clean up the area with isopropyl, then post a clear pic of the area mon2 shows.

[irfan-1]

The reason PD2 was taken out we though there was a problem with it because the 19v was not charging or switching the laptop on, then when i add the battery it sucks all the 19v down to 0v, but after taking the PD2 out it was still the same

[pc_okay]

Hello,

Time to buy à microscope my friend !!! and some stuff to Repair your Little mess…

For the original problem, your charger may just shut off because Of overload due to shortage on your motherboard.

if you have a multimeter you can Check WITHOUT AC ADAPTER AND BATTERY résistance to ground on the positive pin Of the dc jack on the motherboard With and without dc jack connector attach (Look at the photo for détail)
Red probe on the ground (like usb port) and red probe on the dc.

The you can do the same on PD3 both side. (Red probe on usb port and black on PD3 ends)

[irfan-1]

I tried with ac adapter but without battery and it all shows 19.9v

[mon2]

The area in post #11 needs to be cleaned up. Do not continue till it is. You are at risk of more damage to the board.

Search for a friendly local cell phone repair shop. This cannot be more than $20 usd - imho.

[irfan-1]

Yes i will do that thanks

[Metti82]

Hi.

Since this topic is not that old, I wanted to add my similar problem.

I hope this is okay.


Mainboard

LA-H492P


Power supply is “short-circuited” when connected and turn off

PQB01 is broken, short circuit to D S G

I replaced PQB01, broken again

Powering mainboard with 1V to find error does not work.

When PQB01 is removed, 19V remain


Many thanks for your help


Best regards


Metti

[pc_okay]

Hello,

what is DSG???

check résistance to ground after PQB01 and on PRB03
If you find a short to ground, inject 1v on the shorted line and Check if something is getting hot.

Ps: did you replace hp power supply With your bench power supply? That may cause PQB01 to Die and Die and Die…
I suggest to never plug bench power supply when original ac adapter shut off automaticly for Safety reason.

[mcplslg123]

DSG-Drain-Source-Gate