Mesa Nomad head 6L6 problem

[Andree88]

Hi, I've a Mesa Nomad Head 100. After 1h of playing the amp started to make a noise (like a ship, a sort of "whoooooooom") and I switched off the standby getting a "pop" even if the volume was set to 0.
I tryied to turn on again but the sound was back again.. then I watched behind and saw two tubes that were a kind of overheated.
I though that were broke tubes and changed with another quartet that I have. Nothing, the first two positions from left get overheated.
What it can be? I made a video so You can see what happens.
Cannot play with this (I don't want to broke more..) and there's the whoooom that makes problems.
Amp got nothing mods (except mud mod, serial-parallel mod and reverb mod), didn't get shock or rain etc.
It had a problem with pilot light solved (it was a path broken).

I didn't used it from 2 weeks but it was in my bedroom.. and I used it 1h today without problems. It was perfect.
This is the video..

https://www.youtube.com/watch?v=-fE-sNXpzEQ

Thanks all and sorry for my bad english (I'm italian).

 

[domct203]

Are you referring to the blue glow inside the tubes?

Dom

 

[Andree88]

Are you referring to the blue glow inside the tubes?

Dom

The blue glow is in all 4 tubes but now the first 2 from left get so hot and got a very high blue glow after turned on.. If I switch tubes the problem remains in the same position. They get so hot and starts a sound with "whooooooooooooom".. I can't power up the amp.. I'll check a tech..