Welcome to the Dell Community [NAME]  Yes it can still be the DC jack. [URL] The AC adapters "Center Pin" communicates with the system to inform it of the type and wattage. So the laptop will function but at a degraded condition. The DC jack on the laptop should look clean and intact like this. [IMAGE] If it does look like this then it could still be the jack. But be prepared that it could be the system board. Best regards and good luck, U2
I have a dell inspiron 15 5559 laptop. Its out of warranty but I'm struggling to have this issue fixed whilst I'm on budget. The issue started with the battery not charging. I plugged in the laptop with my charger and it wasn't charging. When the battery died from not being charged, I then starting using the laptop solely with it being plugged in onto the AC. The battery status would say "plugged in" and show the percentage battery left. I came to this platform to try and find solutions, to which solutions said its either the battery, ac adapter or jack. I've bought a replacement battery and the laptop still wasn't charging, I bought a new ac adapter and still no change in the charging state(i.e. Both the old adapter and new one gave a "AC Adapter = unknown" message when I checked on the BIOS setup, Battery information) I am currently considering buying a jack and replacing that too, but the laptop is working when plugged in from the adapter. It's not charging but it's working. This makes me sceptical about the jack being the problem, because I assume that the laptop wouldn't even function only on the adapter, if the problem was the jack.  I'm trying to figure out exactly what I should do to have it working and charging again, and it's definitely not the battery. Can anyone assist in getting what's wrong so I can finally fix it. 
Dell inspiron 5559 charging problem