... and not in a good way! My trusty Leak blew it's internal fuse this evening when I switched it on. I looked at the fuse and it was blackened. With the top cover off the amp, I fitted another fuse and powered on momentarily. There was a deep hum/vibration from the mains transformer. I was able to switch off before the fuse blew. Would I be correct in thinking that one of the rectifier diodes has gone s/c?