Bench-top time of flight mass spectrometer

A mass spectrometer includes a control system arranged to assess an operational state of the mass spectrometer. When a fault is detected, the control system assigns the fault to one of a plurality of categories, including a first category of faults which may be attempted to be rectified automatically by the mass spectrometer, a second category of faults which may be attempted to be rectified by the user, and a third category of faults which may only be attempted to be rectified by a service engineer. When a fault is assigned to the first category of faults, the control system initiates an attempt to automatically rectify the fault. When a fault is assigned to the second category of faults, the control system causes information relating to the fault to be displayed to the user, including data indicative of the fault and data one or more steps to be taken by the user to attempt to rectify the fault (2000). When a fault is assigned to the third category of faults, the control system causes information relating to the fault to be displayed to the user including data indicative of the fault, and an indication that the user should call a service engineer.