I am having trouble with several Call Pilot 150's. These units have come to my shop via upgrades and moves etc. and were all in good working order. I typically test them and then do a reinstall then put them on the shelf. Some months later I'll take one off the shelf to prep for install and the thing won't come up. The device is "seen" by the system in Maintenance but the "state" is always "not available". Mind you this doesn't happen every time but often enough to drive me crazy! Has anyone else come across this situation?