Yes, try dragging the Multiscan, DblNTSC, or DblPAL files from Storage/Monitors into Devs/Monitors and reboot.  Then choose one of those screenmodes in preferences, and you should be able to get video on your 31khz monitor.

There's a VGAonly file in there too, I never needed it with my A1200 and monitor, but apparently if you include that one it adjusts the frequencies a little to be more compatible with some monitors.. so you might need that too.

Good luck!