Troubles with HP pro x2 612 g2

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

ok, it might be the interesting part.
plugging order :
DC first then Batt : tpc 8120 reading : D 11.9V S 11.9V G 0.23V

Batt first then DC : tpc8120 readings are not the same for the two ICs.
The left one on the photo reads D 4.96V S 4.63V G 4.43V
The right one reads : D 0V S 4.63V G 4.43V

[mon2]

Re: Troubles with HP pro x2 612 g2

On p-channel mosfets, the gate has to be lower than the voltage on the source / drain pins.

If the gate is @ ~5v, the p-channel mosfet is being requested to remain OFF.

When you have the battery first and then attach the dc adapter -> what are the voltages on the charger IC mosfets ?

Your last post has drain @ 0v, is that the same voltage you see on the first of the DCin mosfets ?

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

So, back to the BQ2480S area, in the scenario you asked, batt then dc

the two DC mosfets are at D 8.23 for the "left" one, 0V everywhere else on them (Gates, other D, Sources)
The batt mosfet is G 14V D 8.23 S 8.23

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I did the battery connector measurements too :

if Batt first then DC : the 3 black wires 0V White and blue 3.33V Yellow 3.08V and the 3 red 8.23V

if DC first then Batt : the 3 black wires 0V white and blue 3.33V yellow 3.1V and the 3 red 8.7V

I guess that Batt first then DC is supposedly the correct sequence, as the batt is not supposed to be remove nor disconnected, it even powers the real time clock...

[mon2]

Re: Troubles with HP pro x2 612 g2

Can you post a pic of your battery connector ? Do you not have the usual connector which will also have 2 pins for the SCL & SDA communication lines ?

[mon2]

Re: Troubles with HP pro x2 612 g2

So with battery first, power adapter next, the charger IC is NOT receiving the power from the external power adapter.

This is because the USB Type C controller logic is disabling the power adapter from powering the logic board.

That is, the TPC8120 mosfets are at 0v and this is what you are receiving at the charger IC mosfets.

Respectively, the ACDET pin on the charger IC will remain at 0v since no voltage is present at these DCin mosfets as input.

Then the charger IC remains to enable the battery mosfet only to operate the logic board.

Remove all power -> meter in resistance mode.

Check the resistance from the drain of the the 2nd TPC8120 and to the first pin of the first DCin mosfet at the charger.

We are wanting to know that there are no other components between the USB Type C mosfets and the DCin mosfets. You should read ~0 ohms if measured properly.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

from the drain of tpca8120 left one on the pic to the drain of E6 GUD closest to the charger IC : 0Hms

[mon2]

Re: Troubles with HP pro x2 612 g2

So we have a fairly accurate idea of this design.

The TPC8120 x 2 are the USB Type C mosfets (aka solid state switches) that allow for the external power adapter to enter the logic board.

Then the 2 x DCin mosfets at the charger IC accepts this voltage to power the logic board & charge the battery.

Should have asked earlier but what is the history of this board ?

Any liquid damage ? Just stopped working properly one day ?

Have you tested with another battery ?

Suspecting that the CYPD4125 controller is sensing if the battery is present or not (in addition to the charger IC which also does the same).

If the battery is not detected, the power delivery enables ok. Charger IC receives the voltage @ ACDET and DCin mosfets -> powers the board ok.

If the battery IS detected, the power delivery disables the adapter mosfets. Charger IC does not receive the voltage @ ACDET and DCin mosfets remain OFF -> the battery is forced to power the board.

On the battery connector picture, there are other wires with different colors. Proceed to measure their voltage to ground as well.

Post all readings.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

if Batt first then DC : the 3 black wires 0V White and blue 3.33V Yellow 3.08V and the 3 red 8.23V

if DC first then Batt : the 3 black wires 0V white and blue 3.33V yellow 3.1V and the 3 red 8.7V


reading on the battery itself when unplugged black 0V White and blue 0V yellow 3.1V and red 7.96V

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I bought the pc second hand, from an office employee that got it from work. It was already in this state. The board bears no trace of previous work, no flux or liquid damage.

[mon2]

Re: Troubles with HP pro x2 612 g2

Remove all power. Meter in resistance mode.

Measure the resistance to ground of the white and blue wires.

Also measure the resistance to ground of the yellow wire.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

ok, so you mean on battery itself, plugged to nothing ?

[mon2]

Re: Troubles with HP pro x2 612 g2

Sorry, remove the battery and no power adapter - more concerned about the resistance to ground of the actual logic board signals.

You will measure on the logic board connector where the battery docks.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

ok, so i mesure the resistance to ground of each pins of the logic board battery connector ?

[mon2]

Re: Troubles with HP pro x2 612 g2

yes.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

black 1 2 3 : 0 Ohms
White 4 and Blue 5 : 56KOhms
Yellow 6 : Infinite
Red 7 8 9 : Infinite

[mon2]

Re: Troubles with HP pro x2 612 g2

When the battery is glitched into charging, does the battery charge to the full potential ?

How long does a full charge of the battery last on this unit ?

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

yes, it reaches its 100%
According to HWMInfo, it is at 90% health
It lasts I'd say 3 hours, maybe 4. At the time it was review by tech websites, its weak autonomy was pointed out.

The battery is the first thing I checked, it is not buldged at all, and the health status seems legit

[mon2]

Re: Troubles with HP pro x2 612 g2

Can you confirm the details of your power adapter ?

Post pics. Concerned if this adapter is suitable to power the logic board and charge the battery.

See here (random search):

https://www.staples.com/hp-45w-usb-c...duct_IM18V8746

This adapter features the use of 20V, yet the voltage is 12v. This may be limited by the firmware inside the CYPD4125 or could be a fault of the adapter.

I think it is worth testing with your Nintendo adapter - if the adapter is not suitable, the power delivery contract will not be negotiated.