Previously, Bower et al.  demonstrated a microfabricated vacuum microtriode with an integrated carbon nanotube field emission cathode. One of the main limitations of the microtriode was the inadequate device insulation which suffered from leakage currents and electrical breakdown at fewer than 200 Volts. Here, we report similar micromachined vacuum electronic devices fabricated to withstand voltages in excess of 1000 Volts. The DC electrical characteristics of a microtriode were obtained at grid and anode voltage levels significantly higher than previously reported. The field emission performance of the MPECVD grown carbon nanotube cold cathode is described Implications for future on-chip microfabricated vacuum electronic devices will be discussed.