I mentioned in my Newbie greeting earlier that I had no luck with 4 different speedometer computers,as all immediately flashed and reset over n over as soon as the motor kicked in. I really believe now that the 'black box' (cdi ?...crt? ...whatever ) is not the problem. I think the imprecise way all the units small batterys fit into thier ringed compartments is the true problem coupled with the fact that all of them have that simple 'snap in' battery cover and the vibrations thru the frame are just too much to keep constant battery contact. Proof of this to me is that the Target bought Schwinn computer with the red trim on 3 sides of the face (a current product at Target,at least here in Ca. $20) uses a much larger lithium battery,about nickel size and best of all it has a large quarter sized THREADED battery cover with a dense rubbery disk that presses against the battery when the cover is screwed down ... I added a second circle of rubber over that one made from an old bike inner tube. Voila ! this worked perfectly over the entire 22 mile trek I rode this morning. Anybody having the same problem I had with resetting computers, this is the one to end your woes.