WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
Just to be clear - lights up - what colour? The grid never lights up. The filament only glows orange if you put too much voltage across it. It should be deep red or not visible at all. When everything is working the anode lights up greeen.