DawidJordaan:
Hi I stated recently with arduino.
I have a UNO rev3.
Today I discharged a 100uF capacitor between ground and A1.Is all lost or can I only replace the ATMEGA328P-PU micro controller.
And can it be replaced by any ATMEGA328P-PU or do I need one that is prepared beforehand?
Most likely a replacement 328P will fix the problem, but there is no guarantee of that. Unless you own a AVR hardware programmer or another arduino board to facilitate burning a bootloader into a blank chip, you are better off buying one pre-installed with the Uno bootloader. Several vendors offer such.
Lefty