mk iii reverb issues

I seem to be having a slight problem with my reverb on my mk iii (simulclass, geq, Rev combo.) I'm hearing a secondary signal while using my clean channel that is very distorted, almost as if it is combining with the lead tone, but the distorted tone is very quiet compared to the normal clean signal. My thinking was it should probably be fixed before it becomes a major problem.
While I am definitely not an amp tech, my guess is that the reverb tube is going out.
Anyone run across this before?

This is a known problem (background distortion on clean when reverb used). I put up with it and used external reverb fx for years then contacted Mesa. Mesa provided me with a fix and a copy of all their mk3 boogie mods and fixes.

Essentially an extra connection to earth from a wire on the reverb transformer. Cleaned it all up. Was easy to do myself.

"120k resistor on the red lead from the smaller reverb transformer to ground." . Not in series.

I grounded it to the reverb tank phono sockets earth which is nearby.

With it now super clean, I also modded the amount of reverb level itself with a 10k 1/2 watt resistor in series on the black cable that goes from the PCB to the fx return socket. Added loads more depth of reverb. You could try 3.3k but that was not as good a range for me - I wanted everything up to Dick Dale and now have it.