Comair, Rotron, Major DC

Model # JQ24F4V

The fan is compatible with all Tektronix  TDS500, TDS600, and TDS700 series oscilloscopes.

This includes: TDS510A, TDS520, TDS520A, TDS520B, TDS520C, TDS520D,  TDS540, TDS540A, TDS540B, TDS540C, TDS540D,

TDS544A, TDS580A, TDS620, TDS620A, TDS620B, TDS640, TDS640A, TDS640B, TDS680A, TDS680B, TDS680C, TDS724D, TDS744,TDS744A, TDS754A, TDS784A, TDS784B,TDS784C, and TDS784D (the list is not complete).

Contact me if you have any questions or  not sure if it is compatible with your scope.