Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help!!

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

I think that both PQ36 and PQ37 are suspects.

Remove PQ36 with flux, heat, low air pressure and patience. This is the high side mosfet used to charge the battery. It may be leaking.

With enough charge on the battery, test again but with PQ36 removed.

Does the logic board boot ok now with the battery installed ?

Next, attach the external power adapter with the battery still installed. Boots like normal?

PQ37 may also be required to be removed. This is the low side mosfet of the charger.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

I think that both PQ36 and PQ37 are suspects.

Remove PQ36 with flux, heat, low air pressure and patience. This is the high side mosfet used to charge the battery. It may be leaking.

With enough charge on the battery, test again but with PQ36 removed.

Does the logic board boot ok now with the battery installed ?

Next, attach the external power adapter with the battery still installed. Boots like normal?

PQ37 may also be required to be removed. This is the low side mosfet of the charger.

Thanks so much, I was in the middle of doing what you suggested and my dam hot air gun element packed up. And my soldering iron ceramic core cracked shortly before so I'm waiting on a new rework station before I can continue. FML!!

[xiongyang]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

首先要确定电池和kbc还有充电芯片的通讯是正常的

First of all, make sure that the communication between the battery and the kbc and the charging chip is normal


.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

I think that both PQ36 and PQ37 are suspects.

Remove PQ36 with flux, heat, low air pressure and patience. This is the high side mosfet used to charge the battery. It may be leaking.

With enough charge on the battery, test again but with PQ36 removed.

Does the logic board boot ok now with the battery installed ?

Next, attach the external power adapter with the battery still installed. Boots like normal?

PQ37 may also be required to be removed. This is the low side mosfet of the charger.

Ok so i removed PQ36 as you suggested and there was no change. I spoke to someone else who suggested that PQ39 might be the culprit for switching between battery. what are your thoughts? @mon2?

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Certainly do test the mosfet @ PQ39. This is the battery mosfet that enables / disables, varying on if the adapter is connected. When the adapter is connected, this mosfet should remain OFF and vice-versa if only the battery is used.

If the mosfet is leaking then yes, could be an issue.

Remove all power / no battery. Meter in resistance mode.

Check the resistance across the mosfet pins like before:

source & drain
source & gate
gate & drain

post each measurement.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Certainly do test the mosfet @ PQ39. This is the battery mosfet that enables / disables, varying on if the adapter is connected. When the adapter is connected, this mosfet should remain OFF and vice-versa if only the battery is used.

If the mosfet is leaking then yes, could be an issue.

Remove all power / no battery. Meter in resistance mode.

Check the resistance across the mosfet pins like before:

source & drain
source & gate
gate & drain

post each measurement.

Ok so i have done the following. I removed PQ36 and tested without it on only battery and no change.

I then swopped out PQ39 and no change there either. here are the results of PQ39 with the swopped MOSFET.

source & drain = 8.23 Kiloohms
source & gate = 2.34 Megaohms
gate & drain = 2.65 Megaohms

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

If you have removed PQ36 and with battery only, then the battery will not be able to power the logic board. Was this the result you saw during this test?

This is since the battery power path has been removed when this mosfet was removed.

Respectively, attach the adapter and the adapter should be able to power the logic board normally (with PQ36 missing). Please confirm.

source & drain = 8.23 Kiloohms

This is a bad reading - it is too low for a mosfet - can you confirm the measurement? However, the reading may be influenced by some other component on the logic board.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Ok so i removed PQ39 to test without any influence of other components and here are the readings.

source & drain = 20.4 Kiloohms
source & gate = OL
gate & drain = 2.34 Megaohms

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

source & drain = 20.4 Kiloohms

This is a very low resistance for a mosfet. It is defective and must be replaced.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

This is a very low resistance for a mosfet. It is defective and must be replaced.

Ok, so im not sure what im doing wrong here but as you can see in the attached pics if i measure from source to drain i get different readings depending on where i probe. taking the below readings into account is it still too low? or do you think this mosfet is defective?

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Review the mosfet test methods here:

https://www.homemade-circuits.com/ho...using-digital/

You will use the diode mode of your multimeter. One one orientation of the probes, the meter should conduct. Block when the probes are reversed.

Post your measurements.

The diode mode is 2 clicks to the right on your meter face.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Review the mosfet test methods here:

https://www.homemade-circuits.com/ho...using-digital/

You will use the diode mode of your multimeter. One one orientation of the probes, the meter should conduct. Block when the probes are reversed.

Post your measurements.

The diode mode is 2 clicks to the right on your meter face.

Ok so i did as you recommended, thanks for the info.

So when i measured from source to drain i got OL as it suggested and then when i moved red probe to gate momentarily and back to drain the numbers start counting up and then i get OL again. if i repeat the steps this continues.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

If you have removed PQ36 and with battery only, then the battery will not be able to power the logic board. Was this the result you saw during this test?

This is since the battery power path has been removed when this mosfet was removed.

Respectively, attach the adapter and the adapter should be able to power the logic board normally (with PQ36 missing). Please confirm.


This is a bad reading - it is too low for a mosfet - can you confirm the measurement? However, the reading may be influenced by some other component on the logic board.

As you suggested ive removed PQ36 and the laptop still does the same. It wont power on with just battery connected and then when i connect AC as well as battery it takes forever to power on but it eventually comes on. with battery removed it powers on much faster.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

do you perhaps have any further ideas based on the findings listed??

1.So when i measured from source to drain i got OL as it suggested and then when i moved red probe to gate momentarily and back to drain the numbers start counting up and then i get OL again. if i repeat the steps this continues.

2. As you suggested ive removed PQ36 and the laptop still does the same. It wont power on with just battery connected and then when i connect AC as well as battery it takes forever to power on but it eventually comes on. with battery removed it powers on much faster.

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Remove the adapter & attach only the battery (with some charge).

Measure the voltage directly on the battery.

Then measure the voltage on the main logic board power rail.

Do you read a voltage with only the battery? You should not since the battery mosfet (PQ36) is removed.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

Remove the adapter & attach only the battery (with some charge).

Measure the voltage directly on the battery.

Then measure the voltage on the main logic board power rail.

Do you read a voltage with only the battery? You should not since the battery mosfet (PQ36) is removed.

Ok so i measured the voltage on the battery and im getting nothing. im also getting no power on the main power rail.

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

If the battery is out of circuit and on your work bench - do you read any voltage on the battery connector? You will have to locate the + and - (ground / black probe on your meter) to confirm.

Specifically, does the battery you are using even have a charge and it appears to be dead once you attach it to the logic board ?

Without the battery - does the logic board power up with only the adapter like normal? It should.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

If the battery is out of circuit and on your work bench - do you read any voltage on the battery connector? You will have to locate the + and - (ground / black probe on your meter) to confirm.

Specifically, does the battery you are using even have a charge and it appears to be dead once you attach it to the logic board ?

Without the battery - does the logic board power up with only the adapter like normal? It should.

So with the battery out i tried to measure if there was any charge but from what i read you cant just measure on the positive and negative. i did that and i got nothing. Battery has some protection built in to prevent this.

I also tried with battery connected and then connected AC and the LED went from white to amber to showing that it was charging the battery. Board powers on absolutely fine without the battery installed and only on AC.

PQ36 is now back on the board.

[mon2]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

So, now the battery is charging ? Leave it for a while to see if the battery is able to charge enough to power this board since PQ36 is back onboard. For the charging voltage, the high and low side mosfets need to be working to dial up the voltage required for the charging cycle.

[roxboy1984]

Re: Hp 15-P104NI Laptop switches off with new Battery when AC unplugged!! Please help

So, now the battery is charging ? Leave it for a while to see if the battery is able to charge enough to power this board since PQ36 is back onboard. For the charging voltage, the high and low side mosfets need to be working to dial up the voltage required for the charging cycle.

Well when i say its charging, the battery led indicates the battery is charging based on the amber color. but it has been doing this from the beginning. as soon as i remove the AC it doesnt switch over to battery. but i shall leave it for a while and try it again to make sure.