Jim,
Please give our Supprt Department a call at 888-200-5129 and we'll get it fixed. In the meantime, try unplugging the 740 and there is a switch on the bottom of the unit labelled Batt on/off. Use a toothpick and slide it off and then back on. Then plug the 740 back into power. This may reset and fix it, if not please contact us.