Started target density fluctuation vs fan speed/raster size tests: Raster=1x1 mm, 28 uA. fan speed=24 Hz, 40 Hz, 50 Hz, 60 and 70 Hz. Septum (r) went to 7.7K. Turned to 5 uA while change raster. T_septum=7.4K. Then repeat with raster size of 3.5x3.6mm (max).