Thinkpad x220t wont start/boot/power on

Hi guys, I have a problem with my thinkpad x220t

Yesterday evening I shut it down and went to bed.
Today morning i wanted to start it and nothing happened.

I tried plugging the battery out and in again. Still nothing.
Another problem is, that no LED is glowing. Nothing. Not even the charging LED on the back.
Altough it should charge, because i have both the battery and A/C plugged in.

Other things that i tried are:

• The thing with plugging everything out and pushing the power button 10 times for 1 sec then 30sec
• Removing the CMOS battery, and trying to start it with and without it.
• Using the Ram seperately
• I have unpluggen almost everything i can.
• ...

I you have other suggestions please answer. I use that thinkpad for university and can't afford another.

EDIT:
Could it be, that the DC-Power Jack is broken? If yes how can I be sure that this is the case?

EDIT2:
Ok, i have checked the power jack with a voltmeter, and all voltages are at 20,27 V or so, I think that is ok.
And i have found this, i think i will have to replace the mobo, right?