Weird mobo issue in Dell Laptop

[SprinterTech-WI]

happy Monday morning all! and hope you had a Happy Easter!

Ok so I have this Dell laptop that came in, only works on the battery will not powerup or show any lights when plugged into ac power - sounds like a jack problem..... well I tried a few known good working power adapters first on it, then tore it apart..... got access to the jack (which means tearing EVERY part out!) it looked fine, anchored solidly, soldering looks good, tested it and it is gettign power through it... so jack is good, but for some reason I am not getting any lights, nor is it powering anything on..... there are indicators on the board that light up when the battery is plugged in, but don't do a thing when the ac adapter is plugged in with or without the battery.

Any ideas? I can't find anything else wrong on the board, but I am not the most knowledgeable board level (I know a decent amount, but no expert).
I'm looking to see if I have any spare mobos hanging around for this one, otherwise it may be a lost cause.....

 

[Tekko]

When you plug the AC adapter into the laptop does the LED on the adapter itself turn off or does it stay on?

 

[SprinterTech-WI]

When you plug the AC adapter into the laptop does the LED on the adapter itself turn off or does it stay on?

stays on, and I'm getting the correct voltage on the other side of the jack

 

[Tekko]

Just brainstorming here; does the batter charge when its plugged in?

 

[SprinterTech-WI]

Just brainstorming here; does the batter charge when its plugged in?

nope.... it doesn't. Windows doesn't recognize that it's plugged in either

 

[Boston Pro Comp Serv LLC]

What the model # of the laptop?

 

[SprinterTech-WI]

What the model # of the laptop?

DELL 6400 PP20L

I was playing around with things..... and interestingly enough when I have both the battery and cord plugged into just the board, turn it on the blue leds turn on, then I can remove the battery and it still runs.... so I'm going to put it back together and try a few more things......