Greedy Turbo TImer

[rx7-mark]

Hi
I seem to have a problem with my turbo timer and just wondered if any you had had this happen or new why it was happening?

Over the cold spell, my battery died so i had to jump the car, now before this my turbo timer was working fine, after the jump  it wouldnt turn on so i unplugged it and plugged it back in. It turns on now but all i have now is a u coming up thats it, nothing else..... Do any of you know why this is? is there like a pre set button or something? i bought it off a chap off here so have no manual.

Thanks