Taking a quick look at the schematic, the transformer's primary has two windings, allowing it to be reconfigured for 120V or 240. The windings should be in series for 240V, or in parallel for 120V.
It uses linear regulators (well, except for the high voltages...), which do not auto-adjust between the line voltages.
I expect that you will need to rewire your transformer, and also increase the fuse rating (likely double to be double the current value).
The obligatory warning is that this contains a CRT, which will act as a capacitor, storing many kV. Be careful.