This is really easy, but helpful mod for AI amps. After a few times of thinking something was wrong with my amp, I noticed that I had mistakenly pressed the mute button. Easy fix. Get a red stick-on dot, get a paper punch, punch a smaller dot out of a larger dot and stick it on the mute button, which should fit just right. Voila! Now you can press the mute button on purpose at a glance. Did AI actually make the mute button red at some point?