The gauge tube on the 5975 can fail in what the user feels is a short life span because it is on all the time. Failure is indicated by the LED status on the tube and readings of 9.99 or 0. The gauge tube life can be extended by using a command, pre run macro. In the method information box make sure pre-Run macro is selected. Place gauge_off in the instrument control field. The gauge will turn off for every run and back on when the run is finished.