Chinese laser i think its broken! Help Please!

Hi,

I have one the cheap chinese laser (K40 C02 Laser). Last night I was just running it as usual and then it stop cutting and flashing out the back of the machine. So i switched off. Turned it back on with low power tried to run it again. I had a quick look at the tube while it was running (Cautiously) and the the laser appeared to be firing backwards (ie not at the mirror but at the case) the other end of the tube!!? So that makes me think the tube could be ok (wishful thinking)? Could it be the power supply has shorted?

any help/ideas/comments would be greatly appreciated.

Many thanks

Phil

Sounds like the rear mirror burned through or I think these fall off (the epoxy breaks) anyway probably a new tube needed!