Mesa Mark III volume drop

[spawn802]

Hi, I am a long time lurker, but I have learned alot from this forum over the years. I figured I would ask about my Mesa Mark III issue.
I am getting an intermittent volume drop that I have narrowed down the the effects loop. If the loop is being used I will randomly lose half my volume and it doesn't seem to happen if the loop is empty. I tried cleaning it with Deoxit but it didn't help.
The Mesa is a purple stripe with simulclass, reverb, and eq.
Any help or recommendations is much appreciated.

 

[Crunchtime]

According to owners manual, v3 is the preamp tube for the loop. Try changing it.

 

[spawn802]

Well I feel like a dumbass. While in the process of changing preamp tubes I started hitting the pedals in the loop. It seems the culprit was a Boss Tremolo pedal. After taking it out of the loop the problem seems solved and hasn't come back. I should have checked the pedals themselves sooner. Thanks for the help though Crunchtime.