The first and the second arduino were broken in seperate projects looong time ago.
Anyway, i had connected the arduino to a l293 motor driver - standard wiring nothing special.
Never even once was 'magic smoke' released from any of the components.
The whole robot still works as intended but i am unable to program it.
I think that the megau8 is at fault here....
The TX light faintly glows.
Also, i tried putting the arduino into DFU mode after it stopped working but i was unable to find how to set the UNO r2 into DFU mode. I tried shorting the first two wires of the ISCP connector as shown here:
but the arduino is still not detected at all.