i had this problem with my excalibur
kinda looks like this
http://www.jayloo.com/videos/show_vid/2393.html
watch that vid. thats my old excal. it just turns on then turns off really quick then turns right back one right??
sometimes makeing you go into the set up part of the board.
i email'd this problem to tadao a while back and he wote back saying that the tadao board has a thing that turns off the board if theres not enough power getting to it to save the board from looseing its software.
try putting a new battery in it. try getting a good duracell