HP EliteBook 840 G4 charging problem

[mon2]

Re: HP EliteBook 840 G4 charging problem

To be sure that you are on the correct pin, post a pic of where you are measuring this voltage. The ic will have a small dot or dimple to denote pin #1 which will be to the left of this circle. Then count counterclockwise to reach pin #20. This is very important.

If the voltage is 0v, the ic is not being powered.

Locate a nearby resistor that should be ~10 ohms in resistance. Do not have power when checking the resistance of this part.

Place one meter probe directly on pin #20 on the IC. Other meter probe to the other side of the 10 ohm resistor. The measurement should be ~10 ohms. Confirm it.

[Der Schwede]

Re: HP EliteBook 840 G4 charging problem

Yes, you where right. I measured on wrong side but i measured where you told now and no 6 v. And its 141k ohms on that resistor. I send picture with where i m measuring. And when i measure on the resistor ends i get 1,212M ohms ond when i change the probes i get 0,369M ohms

[mon2]

Re: HP EliteBook 840 G4 charging problem

I think you are still on the wrong pin and component. The mustard colored part is a capacitor. The majority of the mfrs will use this color for smd caps and black for resistors. So for example, the part to the right of the cap is the resistor.

Better if you post a pic that will show the entire device. The camera is not very clear.

Is this with your phone or a microscope? Otherwise, try with a phone camera.

[Der Schwede]

Re: HP EliteBook 840 G4 charging problem



Its an cheap microscope. I will post the entire chip with components around taken with camera.

[mon2]

Re: HP EliteBook 840 G4 charging problem

Ok. Remove all power. Meter in diode mode. Touch the meter probes. The meter should tone beep. Now you one meter probe to pin #20 on the charger IC. This is the most left solder pad on the top left side of the chip. Other meter probe to the large resistor marked '100' which is the 10 ohm series resistor. Do you hear a tone beep? Remember, no power to the logic board for these tests.

[Der Schwede]

Re: HP EliteBook 840 G4 charging problem

ok, its beeping.

[Der Schwede]

Re: HP EliteBook 840 G4 charging problem

I saw an video on youtube where he jumped the source and drain from a mosfet becouse the voltage stopped there (exactly like in my case), obviusly to check where the voltage truly ends, i mean wich of them komponet is failed..

But he wouldnt tell the whole story untill i would pay and join his patreon community.

But i think i understand why the jumper was soldered. To measure with the multimeter where the short/broken komponent is. But i just wanted to ask is this safe to do or will something burn?

[mon2]

Re: HP EliteBook 840 G4 charging problem

No, never jump anything till all details are known. If the mosfet was truly not required, the vendor would have done the same to save on manufacturing costs.

He is simply bypassing the DCin mosfets to force the power path onto the logic board. Rather, the mosfets should turn on naturally by way of a boosted gate voltage of ~25v. This voltage is only possible if the charger IC is being powered and is not damaged.

Still with no power, measure the resistance across this resistor marked '100'. It should be around 10 ohms.

Configure the meter into dc volts mode (20v or higher). Connect the power adapter. Carefully measure the voltage to ground on each side of this same resistor.

What are the measurements?

[Der Schwede]

Re: HP EliteBook 840 G4 charging problem

9.9ohms

0v i think. my multimeter is always jumping on some mv without tutching

[Der Schwede]

Re: HP EliteBook 840 G4 charging problem

I was try to jumpwire it before i got your message. i have no patientce. i did it with solderingiron and now it starts. of course i took of the jumpwire or it newer fastened good. so i had to put much heat on board.. i will try to assamble it and see if screen starts and so.. ??? i dont get it. must have been old waterdamage what mad it corossion the Q6010 and what now got soldered again..

[Der Schwede]

Hello. After a long time without tools! I finely got an hot-air-station and could sold the chip what i get an long time ago. So the laptop is working now. Without the small capasitor 😅. Just needs an hard drive Thanks help from Mon2.. Thanks

[quic307]

I have a problem with charging too. But when the notebook is off charging, when is on it's not charging.
I change the bq24736, same issue.

Can you help me for that problem?

Thanks!

[quic307]

I have a problem with charging too. But when the notebook is off charging, when is on it's not charging.
I change the bq24736, same issue.

Can you help me for that problem?

I attached the schematic which is the same for charging. LINK to schematic - https://www.badcaps.net/forum/troubl...0-g1-schematic

Thanks!

[mon2]

Share the voltage to ground of ACDET pin # 6 on the charger IC @ U6000. Carefully measure the voltage directly on this charger IC pin.

Have the laptop powered ON to measure this voltage.

Then laptop off and measure the voltage again.

Be sure that the power adapter is the original and with the recommended power rating for this model.

[quic307]

Share the voltage to ground of ACDET pin # 6 on the charger IC @ U6000. Carefully measure the voltage directly on this charger IC pin.

Have the laptop powered ON to measure this voltage.

Then laptop off and measure the voltage again.

Be sure that the power adapter is the original and with the recommended power rating for this model.

When I measured On = 3.66v
When I measured Off = 2.67v
I use only HP power adapter 90w and 120w (90w needs the NB).

I found the R6030 was faulty and now it is charging....

[Abdurrahman Yahaya]

I really appreciate your conversation.
I have almost the same case with laptop Elitebook G3 with not charging issue, it just blinks power bottom, caps, power led once. No sign of life. I was thinking it was BIOS issues but not. I check everything but almost every power is present, I used Deep seek AI, to guide me, at the end AI suggested I should replace BQ cheap. But I noticed a dual diode close to the charging port has small mark on it, I check all the areas no short.
Following this conversation reading many times to understand, I check the voltage on the diode, I discovered that the charger ID pin was zero, while second pin was 19V.
I checked the charger, charging port, all are good. I try to find the thermal that link to the dual diode, but I couldn't find it. At the end I remove the dual diode, now its working. But I couldn't find the replacement diode in my trash. Can I leave it like that, or I should not give it to owner like that?
Thank you so much

[mon2]

Which dual diode was removed? D6035?

What are the silk screen markings of your logic board? Is there a schematic?

[Abdurrahman Yahaya]

Yes D6035, pin 1 connected to 19V+ while pin 2, connected to charger Id, has 0V, pin 2 with groud has 150 ohms, while Pin 1 with ground is 450 ohms. Now i remove the the diode, the system working fine.
Brand:Hp
Model: EliteBook 850 G3
Board number: 6050A2892401-MB-A01
Schematics not availabale.
Can i give it to the owner? I shouldn't not return it like that?
Thank you

[mon2]

See attached. Found this section of the schematic in other HP models.

Perhaps your logic board is wired in the same way? If yes, the removed dual diode is a 24v tvs diode and is meant to die while protecting the mated lines from a transient that is over 24 volts = OVP (over voltage protection). Once it dies, the dual diode must be replaced else the transient protection feature is lost. The part is not critical so any vendor will work if the pinout matches and is rated at 24v.

[Abdurrahman Yahaya]

I will try and find it .
Thank you mon2🙏🏾