Make sure you understand the difference between resolution and refresh rate.
Look at the HDMI resolutions and refresh rates supported by your TV. They are listed in the TV manual.
Compare them to the resolutions and refresh rates supported by your convertor box.
Pick a resolution and refresh rate that is supported by both devices.
cheers, managed to get it working on 640x480 which is ok but not great, can't seem to find anything re TV resolutions in manual but will check again when I have more time