HP zbook pwr Jack flashes 8x orange 150w adapter

[Antonynl]

I'm stuck with a hp zbook : the charge port flashes white/orange 8 times and than a white light

it has 3.3 and 5v and 19v main power

got 3.3 on onoff switch that gets pulled down by onoff switch but no reaction

Got 1.6v on the middle pin of the power jack.

Using a 150w original hp adapter.

It has suffered minor some water damage

Board DA0XW1MBAI0 REV:1

Any suggestion or hint?

Thanks!!

[mon2]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Remove the battery and test again.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Area's affected by water. One shorted capacitor has been removed.

I don't see any activity on the coils which I checked with an oscilloscope except the 3.3v and 5v power supplies. It looks like that the power on sequence is not initiated when powering on.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

I am testing without a battery

[mon2]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

If not done already - power down -> clean up all the liquid puss with IPA (alcohol) & cotton swab till you can see the bottom blue PCB solder mask.

Then test again.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

I found the problem: the nividia graphic chip is shorted ��

[sikocan]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

What's the resistance of the NVIDIA GPU?

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

It takes 0.5A at 700mV

[Sephir0th]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

This isn't conclusive on my opinion. I'd bet more on a issue with the PCH, especially since the sequence even doesn't reach the point where the GPU will be activated.

Unfortunately no resistance measurements of the coils shared so far, so almost nothing to work with.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Or 128 ohm

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

So one question in terms of voltage injection: when a certain power rail like here the gpu takes 500mA at say 700mV: is that gpu for sure toasted?

[Sephir0th]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Since nobody else responds:

I think I have already told that this isn't a conclusive result, as long as no additional measurements are shared. You shared something about 128 Ohms without any relation instead, which isn't very helpful. If there is meant the GPU_Core resistance then it is way higher than expected. A shorted GPU can take 2 or 3Amps or even more and I have also admitted that the GPU can't be the cause of the actual behaviour you have observed.

But maybe you just don't want a proper repair attempt with the device in question.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

So in your view the gpu could be just fine? I have to admit that I not a 100% sure which is the reason I asked.

I will check each coil to see if I see any signal on the mosfet and gates of the mosfets which indicates that that power supply is activated in the power sequence.

If non of the power supplies gets started could mean that the bios is corrupted.

I will measure each power supply load resistance and report back later on

Thanks for your help Shepir0th!

[Sephir0th]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Best would be to share a pic of the board, with voltages and resistances written near the coils. Then we can decide where to start.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

A 450k 5.26v
b 30k 3.38v
c 500k 5.26v
d 128k 5.26v
e 52 1.052v

f 7.5
g 7.5
h 3.6
i 3.6
j 3.6
k 3.6
l 18.5
m 46

n 1.5
o 1.5
p 1.5

q 112
r 256
s 800k 5.094v

[Sephir0th]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Okay, this all looks good so far. Sequence is stuck at 1.05V for PCH but no obvious shorts at the power rails visible. But I have two questions:

- I wasn't able to identify the controller for the main memory (RAM) so far. Are there any hidden coils underneath the black tape or similar?

- and back to the liquid damage. Want to know how it looks like now. Hopefully not like in the initial post.
Since the issue probably isn't at the power rails we have likely unfortunately a logic issue instead, so my guess right now. If the RAM controller got found and measured fine, we have to dig more deeper to what the liquid damaged areas connects and to find out whether EC and PCH are indeed still healthy and hopefully we have just a failed transistor or similar semiconductor instead.

Exposed areas seems to be at least related to battery charging (pic 3) and to VMEM for the GPU (pic 1 & 4). Not sure what is affected when looking to picture 2, but damage doesn't looks so serious comparing the other pics.

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

you are right that I missed 4 coild underneath that black plastic:

A2 88K 2.500V
B2 600 1.20V
C2 5.6K 1.8V

D2 4.5K 12V (battery driver)


measured with no ddr memory

I agree that this could be a problem with on of the opamps that determines of all the voltages are there to instruct/signal the processor.

I have taken pictures of all the arease that are affected by the water but I will double check them

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

I have found the problem: there was just a little bit of solder around a tiny capacitor that caught my eye: removed it and it starts up.

Thank you very much for your help and encouragement to not give up. I learned a very valueable lessons on voltage injections: the assumption that a cpu or gpu takes 700mA at 500mV doesn't mean that it is toasted: is would if it measures say less than 1 ohm? I searched on voltage injection here on badcaps and found some very good information but not this specific situation.

[Sephir0th]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Well, there isn't actually a simple answer. Just staying at intel, It doesn't even only depends on the generation of the CPU/GPU but also the model to roughly know what to expect, let's say +/- 1 Ohms.
For me a Clear short at a CPU supplying rail without considering anythibg else is everything below 1 Ohms and on GPU rail even a full short can be still fine. For example, had a working GTX1080 which measured 0.3Ohms to GND. Internal resistances of the multimeter probes probes was 0.2Ohms on good days, so almost impossible to say. In these cases you doesn't decide only from resistance but also from behaviour to assume a fault (or not). At least myself is working like this when trying to get a first overview of a board in question. Can't speak for others

If everything else is ruled out, you call it a no-fix by this process of elimination.

Edit: Congratulations for finding the fault!

[Antonynl]

Re: HP zbook pwr Jack flashes 8x orange 150w adapter

Very interesting: even 0.2 0.3 ohm measured which is what I measure for a full short with a Fluke 177. In other words very tricky.