HP Elitebook Folio 9480m Fake charge after adapter unplugged

[classicandy]

Hi everyone

I have this HP Elitebook Folio 9480m that continues charging even after the Adapter has been unplugged.

No sign of spill or corrosion on the motherboard. I have replaced Charging IC [BQ736] and no luck.

No schematic available but the charging section and some other components seems to be similar to that of Folio 9470m and Elitebook 840 g1.

Please I need assistance on this. Thanks

[mon2]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

Hi.

1) post the full markings of the first 2 mosfets connected to this charger ic.

Then check the resistance of each mosfet to see if they are shorted. Power down and remove the battery. Then meter in resistance mode.

2) see the resistance chart at this URL:

http://electronicsbeliever.com/how-t...-is-defective/

3) next, with battery & ac adapter attached, what is the voltage of ACDET?

Remove the AC adapter, what is the voltage on ACDET?

[classicandy]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

Hi.

1) post the full markings of the first 2 mosfets connected to this charger ic.

Then check the resistance of each mosfet to see if they are shorted. Power down and remove the battery. Then meter in resistance mode.

2) see the resistance chart at this URL:

http://electronicsbeliever.com/how-t...-is-defective/

3) next, with battery & ac adapter attached, what is the voltage of ACDET?

Remove the AC adapter, what is the voltage on ACDET?

Thanks for quick response.....

Page not found in the link you sent. Seems broken

[mon2]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

http://electronicsbeliever.com/how-t...-is-defective/

[classicandy]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

http://electronicsbeliever.com/how-t...-is-defective/

Thanks for this info, it is very helpful. I haven't been using Resistance Check to test MOSFETs before. It is usually Physical inspection or Continuity test.

However, i was able to detect the MOSFET [Q6011] that seemed to be the problem BUT after removing the MOSFET, I decided to read it out of the board. It is reading normally meaning it is not defective. The empty space for the Q6011 MOSFET is still reading that it is defective.

[mon2]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

1) Post the readings on Q6011 PCB pads.

Resistance between SOURCE & GATE ?

Resistance between SOURCE & DRAIN ?

Resistance between GATE & DRAIN ?

2) Then do the same for mosfet Q6012.

3) Power up -> meter in DC voltage setting -> what is the voltage with adapter connected @ ADP_DET ?

Remove the adapter -> what is the voltage with battery @ ADP_DET ?

[classicandy]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

1) Post the readings on Q6011 PCB pads.

Resistance between SOURCE & GATE ?

Resistance between SOURCE & DRAIN ?

Resistance between GATE & DRAIN ?

2) Then do the same for mosfet Q6012.

3) Power up -> meter in DC voltage setting -> what is the voltage with adapter connected @ ADP_DET ?

Remove the adapter -> what is the voltage with battery @ ADP_DET ?

Thanks so much. You are a lifesaver. I have been able to fix it

[classicandy]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

Thanks so much. You are a lifesaver. I have been able to fix it

It turns out it was Q6012 MOSFET that was faulty. The internal diode in Q6012 MOSFET was defective. I have replaced both Q6011 and Q6012 MOSFET and the motherboard is working properly now.

Thanks again

[Mark3000]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

It turns out it was Q6012 MOSFET that was faulty. The internal diode in Q6012 MOSFET was defective. I have replaced both Q6011 and Q6012 MOSFET and the motherboard is working properly now.

Thanks again

Hello

I have the same problem with the power supply, what did you replace Q6011 with? It is marked "E4 VUD" I found no data about it....

Thanks

[SMDFlea]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

Hello

I have the same problem with the power supply, what did you replace Q6011 with? It is marked "E4 VUD" I found no data about it....

Thanks

PEA28BA https://www.badcaps.net/forum/showpo...65&postcount=4

(@mon2 ,the LG fridge is mine )

[mon2]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

Texas instruments charger chips like to use N-channel mosfets.

The parts are very common and have the usual 1-2-3 for source; pin 4 as gate; 5-6-7-8 for the drain.

Locate any donor board and the first 2 DCin mosfets will most likely be N-channel version. Confirm it and replace to test.

[mon2]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

Lol 😆

[Mark3000]

Re: HP Elitebook Folio 9480m Fake charge after adapter unplugged

PEA28BA https://www.badcaps.net/forum/showpo...65&postcount=4

(@mon2 ,the LG fridge is mine )

Thanks a lot