Station KMXA(AM), Aurora, CO (FID 10057) has experienced significant component failure in the antenna tuning unit of one of the towers and the phaser in its nighttime directional antenna system. Because the nighttime array is a complex (six tower) system, this component failure apparently resulted in possible additional electrical stresses that were not immediately apparent, and a simple part replacement did not return the system to normal conditions. Consequently, a complete analysis and retuning of the system may be necessary. Therefore, the licensee requests Special Temporary Authority for operation at 25% of the authorized nighttime power using the daytime antenna pattern. (This operation will apparently not result in an interference situation since the westernmost US class A station on the frequency is also operating on a low power STA.)