Troubles with HP pro x2 612 g2

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

found it shorted, so replaced it just now, by one coming from a similar architecture laptop

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I did not work on the board since we last chatted, las time I lost all voltage battery and dc after replacing hidrv mosfet. I replaced it again today, I mean an hour ago, because i found it shorted, though it wasn't when i soldered it. With the new hidrv mosfet coming from the similar architecture laptop, battery works again, but dc still 5V

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I'm going to bed. I'll work on this board tomorrow for sure. Good night, or good day i should say

[mon2]

Re: Troubles with HP pro x2 612 g2

battery works again,

So on battery, the laptop works ?


Measure the resistance (without power) of both, the high side and low side battery charging mosfets as well.

It will be a good idea to replace both and purchase the replacements for the USB Type C as well as the 2 x DCin mosfets and the charger IC. Not each part needs to be replaced but good to have them as spares, if they are required. Basically want to be able to rebuild this circuit if required. Each are inexpensive from Aliexpress.

this store should have each part (we use them often):

https://www.aliexpress.com/store/173...55d8673b4CmdQY

Plan B is to head on over to @Piernov's with a box of fresh (almond) croissants and this motherboard for repair. Have already selected the mode of transportation.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I sent him a message. But, hum.. though I'm sure this vélocipède is fast, because big whell-big speed, Piernov lives very far from me, in fact it couldn't be further without leaving the country
I found a new cypress IC (usb c) do you think I should try to swap it or is it just a waste of time ?

[mon2]

Re: Troubles with HP pro x2 612 g2

Is the Cypress chip you have from a similar donor board? If yes, then it is worth a try since it will contain the firmware. Do you see 12v on the donor board?

As far as I can recall, it is a Cortex Mx processor that uses GUI tools to create the firmware. Puzzled as to why the logic board would not function when the battery was installed with the adapter. This condition is often linked to defective mosfets.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I must find a suitable replacement for the one tpca8120 that is dead. Of course I found some mosfet of the same size, but only N channel when it need to be P channel

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

well. I suppose I shouldn't try, the donor board is not using usb c to power on, it has a separate standard Dell jack

[mon2]

Re: Troubles with HP pro x2 612 g2

Test the power adapter with another port on the logic board. Flip the power cable by 180 degrees.

Any difference in the voltage output at the mosfet #1 of the type c ?

Interesting find...

https://h30434.www3.hp.com/t5/Busine...r/td-p/7098443

The CCG4 is part of the BIOS update and is updating the usb-c port controller firmware - actually separate from the BIOS, but included in the update

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

there are no other usb c on this board, it's tiny and only has a usb c, a usb a, audio and that's all. there isn't even a video output port.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

do you think i should try again injecting 11.8V on this mosfet ?

[mon2]

Re: Troubles with HP pro x2 612 g2

Check the resistance (without power) of the 2 x DCin mosfets @ charger IC.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

4.4KOhms, there is a 4K resistor on the road

OH ! I tried to put back the leacking tcpa8120
the first one smoked and now has a hole in it. The usbc V lines are now shorted

Removed the two tpca 8120, usb c no longer shorted, 5V waiting on the first TPCA drain pads

[mon2]

Re: Troubles with HP pro x2 612 g2

Ok. Leave the 2 x TPCA8120 off the board. That should remove them from the equation of this power path from the Type C connector to the charger IC.

Rotate the head of the power adapter to see if the CYPD4125 is able to negotiate a 12v power delivery contract.

Will study the CYPD4125 design but do not believe the mosfets are required to negotiate a valid power delivery contract.

The firmware is applied through a bios upgrade but of course the logic board has to be powered to boot.

Do you have spare N-channel mosfets for the charger IC ? Is that what is with a low resistance of 4k ? Yes, there is a 4k series resistor between the gate pins and the charger IC - that is from the TI datasheet / reference design.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

yes
4KOhms from pin 4 of bq24780s (ACDRV) to the gates of the two E6 GUD mosfets (DC)

what do you think about the strange behavior the pc had when I injected the 11.8V directly at the G8 VUD drain (this mosfet drain is the next pad where the 11.8V could be found after passing through the two USB DC tpca 8120)

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

now that the tpca s are removed, I have bigger pad to solder an inject wire, I can still try again. What do you think ?

[mon2]

Re: Troubles with HP pro x2 612 g2

1) confirm that the first mosfet driven by the 24780S does not have a low resistance to ground. This will be the first of the 2 x DCin mosfets. It should be ok but just confirming.

2) After the above, since the TPCA8120 are removed, there should not be anything else in the power path from the Type C circuit. You should be able to apply the 12vdc from your power supply onto the first 2 x DCin charger IC mosfet.

When you do this, ACDET pin on the charger IC should be a high enough value to enable the same 2 x DCin mosfets. Check the voltage of ACDET.

Also check the voltage of REGN pin on the 24780S. This should be ~6 volts on REGN. This rail is important to create the boost voltage required for pin # 4 of each N-channel mosfet linked to this IC.

Current limit your power supply to be similar to the HP power adapter rating.

HP website notes that 45W is the default power adapter but a 65W is available for rapid charging of this unit. The 65W most likely supports the use of 20V power delivery contracts - like the rest of the industry.

Aliexpress sells small bridge boards ($1-$2 USD) that auto-enable the power delivery contract out of your adapter. That is, a 12v bridge board will select the 12v PD contract provided your adapter has this contract. A 20v bridge board will select the 20V contract, etc.

Cypress sells a small board with a rotary switch to select other voltages - provided your adapter has the same support.

These bridge boards are effectively the same as the CYPD4125 design on your board.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

12V at dc mosfet drain. its gate receive 0 so the 12V stay there. ACDET is at 3V REGN is at 5.1V

[mon2]

Re: Troubles with HP pro x2 612 g2

REGN is low in the voltage. It should be 6v.

With no power, check the resistance to ground of the REGN pin.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

REGN resistance is OL