The pulse height distributions for three different galaxies observed at different voltage settings throughout the mission. The pulse height distribution of the 920–980 Å wavelength region in the SiC 2A spectrum is plotted in gray, with the background distributions from an equally large area under the spectrum plotted in black. Upper: Tol 0440-381, middle: Haro 11, lower: M 100. The drift between the two distributions show that the differential loss of sensitivity for the spectrum and background regions could have a significant effect for M 100, which was observed late in the mission after several detector voltage changes. In addition, for Haro 11 and Tol 0440-381 there is a slight shift, indicating that there might be some effect present.