Chosen Solution

Good morning, my name is Andrea and I’m a hardware technician at the Ministry of Finance in Rome. I have a iMac i5 2011 that does not start anymore. The diagnostic LEDs do not even light up. I changed the power supply but nothing. I realized that the damage is on the motherboard. Is there a fuse or capacitor I can control? thank you

Solved……my problem is video card…..I removed the video card, the mac is back normal, you hear the bong ….. thanks to everyone for help, now i just have to buy a new video card ….. bye from Rome.