The step by step instruction worked pretty good! Thank you very much for this help!
One interesting issue I had was that the battery on the logic board was empty.. the result of this was that the iMac hadn´t booted any more. An alarm signal with 1 beep every 5 seconds came. At the beginning I thought that the RAM wasn´t installed correctly, but the cause was a low PR2032 battery.. all in all I am really happy that it works now with a new battery. I wish you also much success!
Lorsqu'il en aura reçu, il pourra afficher un graphique de sa réputation au fil du temps.
Voici un aperçu de ce à quoi ressemble ce graphique :
Aucun point de réputation obtenu pour l'instant.