Elitebook 840 G6 not getting power from power supply

[Splotsch]

Hello,

my Notebook keeps discharging the battery, even while plugged in. It does recognise the power supply, as in the bottom left corner it says "plugged in".

I have tried multiple original HP Power adapters.

I have also tried replacing the Battery, which didn't change anything.

HP Support Assistant's Battery Test and Power Supply Test claims that all is fine.

I can only use the notebook as long as the battery lasts, then take it out and charge it with a lab bench power supply.

Is there anything else I can do? By the way, i didn't see anything that looks broken on the mainboard.

[Huffer]

Tap esc then F2 as you power up and do the long diagnostic test on the power supply. My best guess is the AC adapter jack has become damaged and it is not routing power to the charging circuit of the battery. 

[Splotsch]

I just tried,

Power Supply says "PASSED", but this time the Battery Test says "BLOWN FUSE (42)"

The battery is new though, so what else could trigger this statement?

[Huffer]

Even a new battery can be bad. When the test says blown fuse I think you understand that is the most obvious answer to the question: "what's wrong"? 95+% of the time when a laptop has trouble charging; its the battery. 

[Splotsch]

But it sounds like there is something wrong with the notebook that caused the battery-fuse to blow, first in the original battery and now in the new one. (I didnt do the battery test on the old battery but i had the same problems with that)

Is this the sort of fuse (in the battery) that one could try to fix with some soldering skills?

Or should i just try another new battery and risk breaking that aswell?

[Huffer]

Contact the seller of the new battery and see if they will replace it free. We absolutely do not know the previous battery had a blown fuse, which is a relatively rare failure mode.

[Splotsch]

Why am I not able to run the notebook just on AC power without a battery installed? With other notebooks I owned this was always possible.

Also, i ordered another new battery, hope that one will work.

[Huffer]

You should be able to do that. Again going back to my older theory that there is something wrong with the AC adapter jack and its connection to the motherboard. 

[Splotsch]

You might be right because the new battery is not working as well ("blown fuse").

A bit wierd though that the power supply test is not detecting any problems while the battery test is.

That probably means my mainboard has to get swapped out?

[Huffer]

Can't entirely rule out a bad motherboard but a bad AC jack can create all these issues. In some cases a bad AC jack might as well be a bad motherboard because the jack is soldered on.