Tests were performed on a Picker Model DGC-1010 capacitor discharge mobile x-ray machine to determine accuracy of voltage and current-time indications, line voltage effects and current drain, exposure reproducibility, focal spot size and location, correspondence between the collimator and light localizer, inherent filtration, half-value layer, radiation output, and tube housing and collimator leakage. Spurious radiation was found to originiate in the tube under certain conditions. These conditions were investigated, and the observed radiation levels are reported. To determine beam quality differences between capacitor discharge and conventional equipment, comparisons were made of half-value layer and step-wedge and phantom radiographs. (Author)