HP zv5120us will not run off DC current. I've already put on a new jack! Help plz!

So I'm fixing (or trying to fix) a friends laptop. It's a HP Pavilion zv5120us. The problem is that when powered on, the laptop will not accept power from the AC adapter (which should be low voltage DC power from the adapter to the laptop right?). It will however charge the battery when the computer is shut off. So it will run till the battery is dead, then charge itself and then you can turn it on again. With the battery taken out and AC jack plugged in, if you try to boot it up the fans will start to spin for a fraction of a second and the LEDs will light for just as long too, but that's it. So power is getting to at least some of the system.

Apparently the zv5000s have similar problems like, no battery charge, no power whatsoever and most of these problems originate from the AC jack. Sometimes the jacks themselves get damaged or the soldering is poor so I took it apart and checked it out. I HAVE ALREADY BOUGHT AND INSTALLED A NEW JACK. My soldering was top notch. The problem persists in exactly the same manner. I have also tested the AC adapter. It has a green LED that comes on when plugged in, and with a multimeter it registered 18.9V on the 200 setting for V DC volts. The AC adapter label says 18.5V so it is o.k. Maybe there's some stupid setting that got switched so the laptop won't run off wall power.

If anything triggers a thought for anyone please reply, I want to get rid of this thing.

 

The motherboard probably has issues in the power circuitry. The lines from the jack to the computer are messed up, but the lines to the battery are okay.

I'd verify that your soldering wasn't somehow shorted, and try running the laptop without the battery. Update the BIOS as well if you can.

There were so many problems with these notebooks, that I think HP extended an offer to repair this for three years after purchase - just to avoid a class-action lawsuit for shoddy design. Google is your friend to find that page on HP's site.

 

The problem is exactly the same as it was before I put the new jack on so I know my soldering was o.k. I'll put the battery in and see if I can update the BIOS. The laptop is over four - five years old though so I don't think HP will do anything for me. I will check though. Thanks for your very fast reply Greg.