Manuals sourced for the FE-5440A O-1824U and TD1215U and FE-5450A
http://www.ko4bb.com/getsimple/index.php?id=download&file=02_GPS_Timing/FEI/FE-5440A/FE-5440A_O-1824U_Cesium_Standard_Service_Manual.pdf
http://www.ko4bb.com/getsimple/index.php?id=download&file=02_GPS_Timing/FEI/FE-5440A/FE-5440A_TD1215U_Cesium_Standard_Service_Manual.pdf
http://www.ko4bb.com/getsimple/index.php?id=download&file=02_GPS_Timing/FEI/FE-5450A/FE-5450A_Portable_Real_Time_Clock_Cesium_Standard_Service_Manual.pdf