Well...
Using the existing parts, no, you can't. However, out of necessity because the transformer decided to start blowing fuses, and a UK cocktail never existed, I have fitted a switch mode power supply and arcadeshop converter board, a 240v monitor isolation transformer and a separate 240v/12VAC transformer for the audio. The only other thing then that is not on 240v is the fan so that just needs a 240v AC fan.
In theory then, job done.
However, FAR, FAR easier to buy a step-down transformer.