[Luxman1050]

Thanks David
but still trying to work out where the heaters connect. As it just shows them unconnected on schematic. Obviously the anode and cathode one connected to earth other into the input of the circuit. Or are the heaters just grounded? I think that's only option its showing but they require 6.5v so where would that come from if their grounded unless the cathode is tied to the heaters and the dc output on the metre provides the voltage!
I cannot see having to put a 6.5v battery somewhere as it's all supposed to fit in a can. So no room for that.
Anyhow just thinking out aloud. Unfortunately I've never made a prob so it's a new adventure but hopefully you can make sense of what info is provided.
Couple more pics with info.
Cheers Chris