I've had my amp head for about a year now and I'm really happy with the sound and volume it can produce. However, there is one problem I'm yet to figure out. Occasionally, seemingly at random, the sound coming from my amp completely dissappears, both through the built in DI and through the amp itself. All the lights on the amp stay on and everything looks normal except for the fact that I can't produce any sound. Nonetheless, it is a quick fix if I'm close to my amp, as all I have to do is click the mute button on and off and the sound returns. Luckily this issue has mostly only occurred during practice, and only happened once live. Still, it isn't something that should be happening randomly at all. Unfortunately, Idon't know what it could be or what to do about it. Some things I've tried are: New lead New speaker cables New power cable Cleaning out the cooling fan Checking the circuit board for issues in the circuit. (although I had no idea what I was looking at) Due to the randomness of this occurring, its hard to tell whether any of these changes are making a difference. Any suggestions for what it might be and what I should do?