I had a thread earlier today about my b-52 amp acting weird. When i turned the gain knob up the only thing that happened was the volume increased but the gain didnt increase. So they said the preamp tubes are shot..i thought that was the case but when i was looking at them all the tubes light up.

Is it possible for tubes to light up even if theyre messed up?

Thanks for the help guys
Just because they light up doesn't mean they're not damaged, lighting up just means they're getting current.

Could be the tubes or something in the circuitry.
My Gear
Cort VX-2V
Stagg BC300
Marshall JCM900 4100 DR
Marshall 1965A
Hartke HA3500 Combo