Carvin V3 head switches channels on it's own. Any ideas?

I’m not sure how much play the head has gotten, but since it’s been in the studio it has always worked fine until recently. Last saturday is when I noticed it, but being as though heads usually are pretty solid I thought my active pickups were running low on juice. This was not the case. What I thought was my voltage running low on my guitar was actually the head switching channels on its own.

I confirmed it yesterday. I changed my battery (on my guitar) and happen to be watching to the head when it happened (& it did a number of times yesterday). Channel 3 (which is the clean channel) was being switched to channel 1 (dirty or crunchy).

Things that I tried:
Unplugging the foot switch.
Switching from 100watts (4 tubes) to 50watts (2 tubes)
Asked owner about the tubes to make sure they were EL34’s, since the head is set up to run those.

If you have any idea of amp head circuity or this has happened to you let me know. We can’t play shows if my rig decided to switch channels on it’s own.