You could run noscreenblank in the background, e.g. from an xterm.

The executable starts a process which runs in an infinite loop, calls osso_display_state_on and osso_display_blanking_pause, then sleeps for 50 seconds, and so on, until it is killed.

If you want to return to the normal blanking behaviour, just kill the process.

Executable: http://armin-warda.de/noscreenblank

Source: http://armin-warda.de/noscreenblank.c

regards, Armin.