I see a used ESE ES-102 Master Clock (circa 1998-2004) has appeared on eBay. Being sold for parts. eBay item number: 195677260971 Inside the unit: display board, DC power supply, and Motorola GPS board plugged into logic board. **Highly recommend checking DC power supply (bad capacitors, diodes, etc.) before powering and usage. ** Good rack mount box for the time-nuts experimenter. Since the full manual is available — OPTIONS that are not installed, could be added (if on empty areas of PC Board) as well as repairs. Uses the Motorola M12+ GPS Receiver and produces various Time Codes (DIP switch settings) for remote displays. Full ESE ES-102 Master Clock Manual with schematic, board layouts, & parts list. https://t1.daumcdn.net/cfile/tistory/99E3D94E5AA44D920D?download greg w9gb