Dark Tubes in Dual and Triple Rec?

[MesaHead]

the other guitarist in my band has a dual rec head.
he's been having trouble with the head sort of shorting out while he plays.
i've been trouble shooting his gear for awhile now and i can't figure it out.
in the back he has six 6l6's aswell as numerous 12ax7's.
four of the 6l6's light up fine, but two of them glow as if they were on standby.
i've tried every switch on the back to get these things to light up but they won't.
there is no half power switch, and the guys as the music store are useless.
i've read the manual several times and there is no mention of this and i can't seem to find an email for mesa/boogie.

we've returned the head and received a triple rec head as a loaner.
here's the stump,
same thing is happenning with this head. 4 of the 6 tubes are lighting up. which would lead me to believe that the half power switch is set to 60w, but there is no half power switch on these heads. it's like mesa forgot them.
what is going on?

[Farview]

Even if there was a half power switch, that would not explain the shorting out.

[MesaHead]

that is true.

the reason i suggested a half power switch problem is because it is more of a severe volume drop, which at low volume sounds like a short.

[MesaHead]

ok, i've figured out the tube issue,

the two tubes that weren't lighting up as much as the others aren't 6l6's.

.......such an idiot.