Mesa Express 5:50 Amp Volume Problem

[Mercury25]

I need some guidance from some of the Mesa Experts...

Last night at a gig my 5:50 started losing volume and had no headroom on either channel.

Also, when switching to 5 watt mode the volume dropped out completely.

I tried swapping out V1 with no change--plus there was little to no light to really work on it.

Could this be a bad phase inverter tube?

Where would you suggest I look first?
I have extra 6L6's and 12AX7's to swap out...

Any suggestions?

Thanks!

 

[phyrexia]

Check the 6L6s and the phase inverter. Then check the other preamp tubes.

 

[Mercury25]

Will do--thanks!

I just need to dig it out of the band trailer and check it out some more.

 

[Mercury25]

Just an update...

The phase inverter tube was bad, popped in a new one and all is good!!

Thanks for the help