Troubles with HP pro x2 612 g2

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

Ok, so i placed the mosfet back. Nothing better. I checked it for short, and the desoldering must have finished it, it now show only 5kOhms from S to D. I tested the pads on the board after removing it, no short, it really seems it s just that it finished "dying" ? I put back to replacement one (that seems good when I check it on the board) but now, not boot at all, but on dc I can read 11.8V on the two USB C V pins

[mon2]

Re: Troubles with HP pro x2 612 g2

If you see 12v from the adapter, the USB Type C negotiations have been performed correctly by the Cypress CYPD4125 power delivery controller and its firmware.

1) Do you see 12v AFTER the 2 x USB-C mosfets ? Same voltage should appear at the first of the 2 x DCin charger mosfets.

Confirm this detail.

2) Next, probe the 2 x DCin charger mosfets for the voltages on each pin:

source (1-2-3)
gate (4)
drain (5-6-7-8)

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

I d'ont have 11.8V anymore, now it stays at 5V
I was goign to give up, thinking it fried for good. But in fact in boots fine on battery now. And you know I had to pull another mosfet, this time from a tiny asus, thes one that used core M in 2016. So this one does not seem to go bad.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

it s back to square one, let s say, but this time it doesn't work on dc at all. Sometime when it get worse it become easier to diagnose the part failing. Could it be the case here ?

[mon2]

Re: Troubles with HP pro x2 612 g2

Remove all power -> meter in resistance mode.

Measure the resistance across the 2 x USB Type-C circuit mosfets:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Check each of these mosfets.

Repeat for the 2 x DCin charger mosfets.

Post each measurement.

If push comes to shove - you can remove one of the USB Type C mosfets (the 2nd one) and apply a normal 12v power supply onto the first of the charger DCin mosfets.

That is, then a traditional 12v power adapter at the proper current can power this beast.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

S to G 50kOhms on both usb c mosfets
S to D and G to D are OL

dcin mosfet are fine, more than 500KOhms on all reads

[mon2]

Re: Troubles with HP pro x2 612 g2

Post the top side markings again of each of these USB Type C related mosfets.

Suspecting that the 2nd one is defective since that is where the injection was placed and it is making both of them look low in resistance for the S-G reading.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

Tpca 8120

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

should I remove it to check ?

[mon2]

Re: Troubles with HP pro x2 612 g2

Yes. With care so other parts do not go flying.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

mhh, i forgot which one was to one i injected...

[mon2]

Re: Troubles with HP pro x2 612 g2

50/50 so flip a coin. Suspecting the first one is ok so it will be the one that is mated with the 2 x DCin CHARGER mosfets to review.

After removal, interested in the S-G readings again of both.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

yep. Second one

[mon2]

Re: Troubles with HP pro x2 612 g2

If you attach the power adapter now (without this 2nd mosfet) - do you get 12v ?

Granted the voltage will not reach the DCin charger mosfets but curious. This is like an open switch / relay now since this mosfet is removed.

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

but i can t manage to see this leaks on the mosfet itself, it s just by probing the pad that I saw to leak disappear when removing it

[mon2]

Re: Troubles with HP pro x2 612 g2

What is the resistance of S-G pins on the removed mosfet ? Is it low ?

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

still at 5v

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

could heating the leaking mosfet had temporarily fixed it ? I mean not fixed it for real, because now it s remove i can't see any leaks

[mon2]

Re: Troubles with HP pro x2 612 g2

Yes - perhaps. Have seen when we purchased some early models of a VOIP handset during a visit to Taipei, the phone LCDs were pixelated now and then. The vendor was somewhat surprised but said they would replace the handset. We opened up the unit and found a fast 8051 microcontroller with a local SRAM IC. The speed (from memory; no pun) was ~150ns or 200ns access time). We proceeded to find the fastest version from Digikey @ 100ns - 120ns access time. While waiting, we reflowed the slower part on the phone -> the display worked 100%. After 20-30mins later (ie. the memory chip was at room temp); the display became pixelated again. Repeat the cycle, fix the display.

When the replacement part arrived from DK, the faster grade of memory worked 100% without heating.

So perhaps yes for your case. To summarize, you had 12v earlier today on the Type C adapter ?

[johnjohnjohnjohn]

Re: Troubles with HP pro x2 612 g2

i had 12V until last test by replacing a leaking mosfet, the hidrv if i rember correctly, or was it the ldrv