Has anyone experienced repeated CCM failures? I have several units that have had the CCM replaced six and seven times. Some will fail within hours/days of replacement. Others have only been replaced once and has lasted for three years and counting. Proffessional tech, only tech at location. Batteries do not appear to be the cause as they rotate between units. All ESD procedures followed. No shorts to frame Static straps in place and clean. Any input would be appreciated. What do you think Carl?