HP EliteBook 840 G2 power problem

[bollin]

I have this weird problem that it sometimes doesn´t detect AC adapter.
The last time it went so far that I had to open it up (because I thought DC jack was broken) but it was fine. LIMIT_SIGNAL was 0v but after applying 3v it started working ok again (2.75v). I tried with 3 different known working adapters so I know that wasn´t the problem.

Where do I start searching if it happens again?

[bollin]

Re: HP EliteBook 840 G2 power problem

Now it has happened again and I don't know what is broken. With battery and adapter connected it says in Windows that it runs on battery only, but it isn't draining it, the charge stays on the same percentage. If I pull the adapter it starts to drain the battery. If I pull the battery it lights up and runs on ac power only. My wife has the same laptop from work, so I can use her computer to charge my battery. It charges in her computer but not mine. Both her adapter and mine works on her computer, and that includes charging the batteries.
Now, I checked some voltages, q6012 has got 12.46v on drain and 19.3v source. There were no 19v on the battery connector at all. I did get a reading of 0.68v on pvadptr with battery connected only.
Can anyone explain how the charging circuit works?

[bollin]

Re: HP EliteBook 840 G2 power problem

Or possibly q6000 pin 4?

[Techtiger]

Re: HP EliteBook 840 G2 power problem

Test the voltage on Battery connector with battery inserted pin 1 to 6, test all pins of charger IC U6000 Voltage? inside the battery there is a circuit it communicate with charger IC &SIO chip “now I am in my types of battery cells I need this much of current to charge ect “

[surecando]

Re: HP EliteBook 840 G2 power problem

Would a Bios update resolve this issue?

[Techtiger]

Re: HP EliteBook 840 G2 power problem

Would a Bios update resolve this issue?

If faulty component no It will not solve the issue

[bollin]

Re: HP EliteBook 840 G2 power problem

No, I have already updated bios but no difference. However, the bios update software requires AC adapter to be plugged in and it did detect The AC adapter when Windows does not detect it.

[Techtiger]

Re: HP EliteBook 840 G2 power problem

No, I have already updated bios but no difference. However, the bios update software requires AC adapter to be plugged in and it did detect The AC adapter when Windows does not detect it.

You can flash BIOS by EPZ2010 Ect but you have to disorder the BIOS chip

[bollin]

Re: HP EliteBook 840 G2 power problem

Yes, but I believe bios is not the problem. Did some probing this morning and without battery PVPACK is fluctuating between 1.35 - 2 volts, as is q6000 pin 4, but they are not shorted.

[Techtiger]

Re: HP EliteBook 840 G2 power problem

Yes, but I believe bios is not the problem. Did some probing this morning and without battery PVPACK is fluctuating between 1.35 - 2 volts, as is q6000 pin 4, but they are not shorted.

test the L6000 coil DIODE mode resistance to gnd it should be above 500ohms

Test the voltage on Battery connector with battery inserted pin 1 to 6, test all pins of charger IC U6000 Voltage?

you have to test all this voltages

[bollin]

Re: HP EliteBook 840 G2 power problem

you have to test all this voltages

I know, my probes are not the best ones so I have to find the resistors that are connected to those pins ( they are not marked) and measure there, and I have not finished taking those measures yet, I will post as soon as I get them

[bollin]

Re: HP EliteBook 840 G2 power problem

Here are the voltages on u6000

U6000 with only AC Adapter:

Pin1: 19.4- 17v
2: 19.4- 17v
3: 19.4-17v
4: 25.3-22.4v
5: 0v - 1.35v
6: 2.5v
7: 0v
8: 3.2-3.3v
9: 3.2v
10: 3.2v
11: 0v
12: 2v-1.3v
13: 2v-1.35v
14: 0v
15: 0v
16: 5.92v-5.85v
17: 5.76v-5.7v
18: 2v-1.35v
19: 2v-1.35v
20: 19.4v-17v

Battery connector:

1: 1.6v-1.1v
2: -"-
3: 3.3v
4: 3.3v
5: 0v
6: 3.27v-3.25v
7: 0v
8: 0v

U6000 with AC Adapter and battery connected:

1: 11.69v
2: 11.69v
3: 0.11v
4: 0.03v
5: 3.28v
6: 2.63v
7: 0v
8: 3.29v
9: 3.29v
10: 3.27v
11: 0.01v
12: 11.69v
13: 11.69v
14: 0v
15: 0v
16: 5.92v
17: 11.42v
18: 11.68v
19: 11.68v
20: 11.68v

Battery connector:

1: 11.68v
2: 11.68v
3: 3.3v
4: 3.3v
5: 0v
6: 0v
7: 0v
8: 0v

I would like to add that in the first measures the voltages were most of the time like the first reading but once every se ond jumped to The second reading, hence the varying readings. There were also a a faint ticking sound about once every second, and that went away with the battery present.

[bollin]

Re: HP EliteBook 840 G2 power problem

Also, ohms at L6000 are about 136 kohms

[Techtiger]

Re: HP EliteBook 840 G2 power problem

Here are the voltages on u6000

U6000 with only AC Adapter:

Pin1: 19.4- 17v
2: 19.4- 17v
3: 19.4-17v
4: 25.3-22.4v
5: 0v - 1.35v
6: 2.5v
7: 0v
8: 3.2-3.3v
9: 3.2v
10: 3.2v
11: 0v
12: 2v-1.3v
13: 2v-1.35v
14: 0v
15: 0v
16: 5.92v-5.85v
17: 5.76v-5.7v
18: 2v-1.35v
19: 2v-1.35v
20: 19.4v-17v

Battery connector:

1: 1.6v-1.1v
2: -"-
3: 3.3v
4: 3.3v
5: 0v
6: 3.27v-3.25v
7: 0v
8: 0v

U6000 with AC Adapter and battery connected:

1: 11.69v
2: 11.69v
3: 0.11v
4: 0.03v
5: 3.28v
6: 2.63v
7: 0v
8: 3.29v
9: 3.29v
10: 3.27v
11: 0.01v
12: 11.69v
13: 11.69v
14: 0v
15: 0v
16: 5.92v
17: 11.42v
18: 11.68v
19: 11.68v
20: 11.68v

Battery connector:

1: 11.68v
2: 11.68v
3: 3.3v
4: 3.3v
5: 0v
6: 0v
7: 0v
8: 0v

I would like to add that in the first measures the voltages were most of the time like the first reading but once every se ond jumped to The second reading, hence the varying readings. There were also a a faint ticking sound about once every second, and that went away with the battery present.

LODRV HIDRV is not working check the 2 N-channel fets

[bollin]

Re: HP EliteBook 840 G2 power problem

Checked both N-channel FETs, they are both ok.

[bollin]

Re: HP EliteBook 840 G2 power problem

Well, i tried updating bios and now it doesn't recognize the charger at all.

[Techtiger]

Re: HP EliteBook 840 G2 power problem

Well, i tried updating bios and now it doesn't recognize the charger at all.

How did you update bios ? Did you save the old bin file ?

[Techtiger]

Re: HP EliteBook 840 G2 power problem

Checked both N-channel FETs, they are both ok.

Q6000 voltage on drain side ? What was the resistance to GND Q6000 Q6001 all pins ? With out any power

[bollin]

Re: HP EliteBook 840 G2 power problem

There was an official update, so I tested it. The charger was recognized by the bios update program, it would not work otherwise. Now nothing happens. I will measure resistance as soon as I get home from work.

[bollin]

Re: HP EliteBook 840 G2 power problem

Q6000 voltage on drain side ? What was the resistance to GND Q6000 Q6001 all pins ? With out any power

With or without battery connected?