Your Princeton Applied Research potentiostat system (273/273A/283/263/263A/VersaStat/6310/BES) has memory just like a computer. And like any computer, sometimes an error gets introduced into the memory, and needs to be cleared. Unlike your computer, the memory is tied to the internal battery, such that turning the system off and on again does not clear the memory or reset the default values. The best way to 're-initialize' (analogous to a re-boot) your system is to turn the system off, and hold down any one of the front panel buttons (for the 273 and 273A, hold down on the LOCAL button at the lower left of the front panel), and continue to hold it down as you activate the main power switch. For the 273/273A systems, the LCD will show "System Re-Initialized", and you can then release the LOCAL button. For 263/263A/283 systems with a LCD on the front panel, the LCD will show "Please Release Key", and the system will be reset after releasing the front panel key. For models without front panel LCDs (VersaStat, VersaStatII, 263A-1, BES, 6310), you can hold in the cell button as you power on the system, and this will re-initialize those units.