HP Pavilion 17-ab091ms - white charging light, but no power

[BMCappelletti]

Hello, everyone.

Got a HP Pavilion 17-ab091ms laptop that has the white light besides the charging connector but does not power on.
No liquid damage, no bumps, nothing. It was working one day and dead on the other.
Charger is fine, outputting 19,5V. 19,5V is also present on the red connector ping on the motherboard.
Power button seems to be fine, as I tested continuity with a multimeter.

It's an Intel Core i7 6700HQ with a GTX960M 4GB model, all on a DAG37AMB8D0 rev. D motherboard, as following pictures.





On a visual inspection there seems to have a blown capacitor (???) on the back side.





I tried to find a board view of this one to at least have an idea of what is that component, but the one posted on another thread here does not seem to be the same model.

So... does anyone know what that component would be?
And, should I try to remove it and power the laptop on to see if it acts differently?

Thanx alot.

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Use a dabbed Q-tip in alcohol and clean up that spill showing in your last picture. Looks like a bit of corrosion but that is a start.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Use a dabbed Q-tip in alcohol and clean up that spill showing in your last picture. Looks like a bit of corrosion but that is a start.

Actualy I have done it, but taking care not to damage anything.
Now I did it again, and use a thin twizzer to remove more.

The caps marked on the image were shorting to ground before. Now the ones in red are fine. The ones in green are still shorting to ground.



Not much. But something differente.

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Remove the ones in green off the logic board and check if the pads are still shorting across their pads on the PCB.

Check if the caps show a short after they are removed from the PCB.

Meter in resistance mode. Check and post the resistance to ground on the caps you are referencing.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Remove the ones in green off the logic board and check if the pads are still shorting across their pads on the PCB.

Check if the caps show a short after they are removed from the PCB.

Meter in resistance mode. Check and post the resistance to ground on the caps you are referencing.

Removed it and the pads are shorted.
No shorts testing the caps. But for some reason I can't get a good read on the resistance. Crappy multimeter leads, I guess.
But they don't seem to be shorted and the pads are.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

If anyone has any idea of what I could try next, please do.
Thank you.

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

hi.

See attached. Meter in resistance mode. All power removed.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Multimeter on 2K scale, it shows 0.026. Varying to 0.030.
The IC seems to be a Z2261QIK FA6617 (not sure about the 66).

[SMDFlea]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Multimeter on 2K scale, it shows 0.026. Varying to 0.030.
The IC seems to be a Z2261QIK FA6617 (not sure about the 66).

Z2261QIK https://cdn.badcaps-static.com/pdfs/...22ef41d6d9.pdf

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Z2261QIK https://cdn.badcaps-static.com/pdfs/...22ef41d6d9.pdf

Yep. I found that link after checking the IC model.
Should I plug power in and check some voltages?
Do I need to check voltages anywhere else?

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Found a very similar board view. Different model name, but pretty accurate with this one.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Well, according to this boardview that component that I cleaned, from the first post, is R5129 (pin 1 +3VPCU, pin 2 LID_EC#). I could measure 3.3V on it. So, at least to this point, 3.3V is present also.
Any more clues is much appreciated.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

UP
(hope it's fine to do that)

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

1) Meter in resistance mode (200 ohm scale is ok).

Check all large coils (grey in color) for their resistance to ground. Red meter lead on either side of the inductor; Black meter lead to a known ground connection on the logic board.

Interested to locate any very low resistance to ground coils (<10 ohms, etc.). Post the location of such a coil if one is found.

2) Meter still in resistance mode (200 ohms). Locate where the DC adapter enters the logic board. Near this area will be likely 2 * mosfets. Post clear pictures of them and also the markings on their top surface.

Next, check if the mosfets are shorted by checking their resistance as follows:

a) SOURCE & DRAIN
b) SOURCE & GATE
c) GATE & DRAIN

Looking for any really low resistance values which may confirm that the mosfet is shorted and needs to be replaced. If one is found, desolder it off the logic board and check their resistance again. If the resistance remains to be very low then that mosfet should be replaced.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

First, the mosfet.
I can see only one near to the power input.



Probably this guy, or some sort: https://datasheetspdf.com/pdf/706795...tors/AON7403/1

I have 19,5V on the first 3 pins on the upper side (considering the photo orientation) and 0 on the last one.
19,5V on the first three pins and 16,5V on the last one, on the bottom.
No shorts on it.

Regarding the coils... could not have a good reading on it. Will buy a new multimeter for that. But what I got are the following measurements.

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Hi. The no reading on the meter is probably ok. Since we are intentionally setting the max scale to be 200 ohms (or similar) - the resistance on the measured coil to ground must be higher than 200 ohms (or whatever the max scale you selected).

Often the meter will show 'OL'. This is ok and means that rail is not shorted to ground.

The readings where you show @ 32 ohms or 52 ohms are also ok as these are likely low voltage rails. Low resistance values are ok for low voltage rails.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Hi. The no reading on the meter is probably ok. Since we are intentionally setting the max scale to be 200 ohms (or similar) - the resistance on the measured coil to ground must be higher than 200 ohms (or whatever the max scale you selected).

Often the meter will show 'OL'. This is ok and means that rail is not shorted to ground.

The readings where you show @ 32 ohms or 52 ohms are also ok as these are likely low voltage rails. Low resistance values are ok for low voltage rails.

Well, that's good. So, what else could I test to determine why the white light turns on besides the charges port but the laptop does not start?
I didn't put those caps back on the board and, if I had a way to do that, I would inject voltage on the shorted pads, to check if something would get hot.
I can buy something to inject voltage on it, but would take some time to receive it.

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Ok. Measure and post the voltage readings on this mosfet.

[BMCappelletti]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

Ok. Measure and post the voltage readings on this mosfet.

19,7V on all.
16,8V on gate.

[mon2]

Re: HP Pavilion 17-ab091ms - white charging light, but no power

The mosfet appears to be turning ON since the gate is lower than the threshold value to allow for the source & drain to conduct.

See attached.

Remove all power.

Meter in resistance mode.

Place one meter lead on the pins 1-2-3 of the same mosfet.

Probe with the other meter lead near the IC (I think the one near the large coil) till you here a meter beep.

We are looking for the IC that is linked to this mosfet. That is, the ~20v enters the board and then through the thick traces mates with a switching regulator. Believe it is the one near the large coil. Wish to be sure it reaches the regulator.

Then the local coil is used to reduce the DCIN voltage to some other value.

After the above resistance check, configure your meter to DC Volts (20V or higher).

What is the voltage at the coil (with reference to ground) when the DC adapter is attached ?

We are confirming that the DC adapter voltage is reaching the first regulator and that the first regulator is performing its duty to turn on and produce some voltage rail.