My Elekit 8200 worked great for a couple of years and then one day, I got no sound. Not on either speaker channel. Not in the headphones. Absolutely nothing. It powers up and lights up the tubes. I've tested the tubes on two different testers and they come back good. I've tried all of the inputs. I've visually checked for any solder failures. I cannot see anything out of the ordinary. So, I want to go through methodically to see where the failure might be. I'm a novice with a huge respect for the dangers of the high voltage, and I'm hoping someone might have thoughts on where to look first. Thanks for any thoughts.