I have the exact same amp and had the exact same probs. A buddy of mine told me to turn on the power only (not the standby) and leave it on for 24 to 48 hours. He told me if you use it for short periods, it doesn’t give it a chance to charge the caps. It worked for me. I still have to do it every couple months because I don’t play for long periods. let me know if it helps.