Need some help please. For the past few weeks, my MT200 has been experiencing a slow death (apparently), until last night it finally gave up the fight. (In the middle of a gig no doubt).
The symptoms started a few weeks ago, with occasional crackling and lowering of volume on the B channel. The A channel appeared fine. By quickly raising and lowering the B channel volume, I could get the volume to return. My first thought was the tubes, so I pulled out a backup set last week, and replaced both tubes. To be completely honest, I'm not really sure that the replacement tubes were 100%. The symptoms would come and go for the last few weeks, until finally last night at a gig, I started to get this loud crackling sound in the middle of a song, sort of similar to the sound you get when plugging and unplugging a guitar into a Marshall stack repeatedly, with the amp volume maxed. Eventually, it just became a long loud noise, and the volume of my guitar just faded away. I reached over to turn down the volume on both channels, but the noise didn't stop. Eventually, I had to turn off the power switch. Fortunately, I was also going direct out of my Kemper amp, into FOH,so I could keep playing.
I'm going to try a new set of tubes tomorrow. Any other ideas, as to what I should check while inside the amp?