HP Pavilion 15-n (U92) not powering on with charger

[classicandy]

Hi, Please I have this HP Pavilion 15 (U92) that is not powering On with only the Charger but does power on when the battery is in it.

I have changed Charging IC [BQ24728] PU2
I have also replaced PQ21 and PQ15 MOSFET

Still no solution

[mobotest]

Re: HP Pavilion 15-n (U92) not powering on with charger

With only the AC adapter connected, what are the readings on all pins of the Charging IC?

Upload schematic if you have it.

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

I have taken the readings of the charging IC [BQ24728] PU2 of a good board and that of the faulty board. Please check the images attached

When the motherboard is switched off, it charges the battery but immediately i switch on the system (with battery attached), it stops charging...... The AMBER LED turns to WHITE.

Please I need help with this laptop.... Thanks

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

With only the AC adapter connected, what are the readings on all pins of the Charging IC?

Upload schematic if you have it.

here is the schematics

[mobotest]

Re: HP Pavilion 15-n (U92) not powering on with charger

My HP laptop (DIFFERENT than your model) had similar symptoms.
If you want to try something quick for a possible fix, replace PQ20.
I had parts corresponding to MOSFETS PQ20, PQ21, PQ14, PQ15 and CHARGE IC PU2 replaced on my laptop.

If you want to isolate to exact component(s), then take readings of Charging IC with only AC adapter, no battery, laptop off.
Your readings OFF_with_Battery doesn't show much difference between Good and Bad.
Perhaps readings without battery will pinpoint something to debug.

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

My HP laptop (DIFFERENT than your model) had similar symptoms.
If you want to try something quick for a possible fix, replace PQ20.
I had parts corresponding to MOSFETS PQ20, PQ21, PQ14, PQ15 and CHARGE IC PU2 replaced on my laptop.

If you want to isolate to exact component(s), then take readings of Charging IC with only AC adapter, no battery, laptop off.
Your readings OFF_with_Battery doesn't show much difference between Good and Bad.
Perhaps readings without battery will pinpoint something to debug.

Readings without Battery has been attached now

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

I did notice Resistor R334 had burnt out and I've replaced it and still no power on with AC only.....

Initially, I noticed the DC Jack had a short between the AD_ID and +VIN because the plastic separating it in the Charging port had broken BUT i have replaced the charging port and still no success.....

[IamPritesh]

Re: HP Pavilion 15-n (U92) not powering on with charger

I did notice Resistor R334 had burnt out and I've replaced it and still no power on with AC only.....

Initially, I noticed the DC Jack had a short between the AD_ID and +VIN because the plastic separating it in the Charging port had broken BUT i have replaced the charging port and still no success.....

DOES ad_id goes directly to IO chip ? COuld be possible that IO chip might have got faulty due to high voltage input.

[mobotest]

Re: HP Pavilion 15-n (U92) not powering on with charger

I would expect pin10 in OFF_Without_Battery to be 0V as it does in mine after mine was functional.

But IamPritesh may be onto something more solid.
According to your schematic, AD_ID is an input for "Smart Adapter Type Check" and produces AD_TYPE which is input to the SuperIO chip.

[bekirsalman]

Re: HP Pavilion 15-n (U92) not powering on with charger

The capacitors of the io chip may be defective therefore the io chip may be defective

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

DOES ad_id goes directly to IO chip ? COuld be possible that IO chip might have got faulty due to high voltage input.

AD_ID passes through 2 resistors, R344 @100 ohms and R337 @10k ohms to AD_TYPE @Pin 71 of IO (U14)

I might have to agree to the possibility of the IO being faulty. Only solution now would be to change it I guess. Or anyway around that???

Is the IO the programmed type?

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

I did notice Resistor R334 had burnt out and I've replaced it and still no power on with AC only.....

Initially, I noticed the DC Jack had a short between the AD_ID and +VIN because the plastic separating it in the Charging port had broken BUT i have replaced the charging port and still no success.....

Its R344 I meant here not R334.... Sorry for the mix up. R334 is the same resistor though but for U93 motherboard instead.

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

The capacitors of the io chip may be defective therefore the io chip may be defective

True, the IO may be defective..... Would try to look for a replacement for it.

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

Thanks for all your efforts @mobotest, @IamPritesh and @bekirsalman ...... Would let you all know the outcome as soon as I get the IO replaced.

[mobotest]

Re: HP Pavilion 15-n (U92) not powering on with charger

Since R344 is part of "Smart Adapter Type Check" circuit, damage to it would make the IO suspect for the problem your laptop has.
In addition to replacing IO, check the diode, resistors, and capacitors that are part of the "Smart Adapter Type Check" circuit.

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

Hello everyone here, so I've replaced the IO with a known working one and yet, no change. It still doesn't Power On with Adapter ONLY. What can I be missing now?

[mobotest]

Re: HP Pavilion 15-n (U92) not powering on with charger

Did you check the diode, resistors, and capacitors that are part of the "Smart Adapter Type Check" circuit?

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

Did you check the diode, resistors, and capacitors that are part of the "Smart Adapter Type Check" circuit?

yea, they seem to be okay

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

I now have 2 exact models suffering from the same issue/problem.

[classicandy]

Re: HP Pavilion 15-n (U92) not powering on with charger

Hello everyone here, so I've replaced the IO with a known working one and yet, no change. It still doesn't Power On with Adapter ONLY. What can I be missing now?

My assumption from this is that, when battery is inserted, the battery triggers something that the AC adapter is no longer triggering which enables it to power On.