Klystron and accelerator technology is forcing voltages and peak powers higher, such as the demand for 500 kV and 500 amperes peak, to power two X-Band klystrons. Modulator technology has not advanced greatly over the last 30 years. Conventional technology (line-type modulators) were never overly concerned about rise time and efficiency. A few years ago, the klystron department at Stanford Linear Accelerator Center (SLAC) undertook an investigation into what could be done in a conventional modulator at 500 kV. We have reported on test bed measurements and shown both conceptual and hardware pictures during design and construction. We have now completed the modulator tank and connected it to an existing high voltage power supply and control system. This paper will give the results of tests into a 5045 klystron load.Presenting Author : Gold S.