Thinkpad X201 no longer boots up, leds lit up for a moment and then slowly went out.

[Thinkpit]

Hello everyone, I have a Lenove Thinkpad X201 tablet that always worked fine, when I turned it on yesterday the power and hd leds lit up for a moment and then slowly went out.
Since then it doesn't start up anymore, nothing at all, no LEDs, no fan, etc. with or without battery and with or without dock, the power supply is ok, I have measured it.

Hope someone can help me, thanks in advance.