my zumo has been on my 990a since new(2008) but very rarely turned on. now I'm going on a gps guided tour but something isn't right. unit turns on only to tell me my map needs an update, should it not work with old maps? any way it will only respond to the to the power button. ok button is also a no. garmins support is closed weekends. any ideas? if I send it back what is the turn around and is it worth fixing? thanks for any help!