This paper discusses in detail the failure mechanisms involved in putout burning-out and SWR increase observed from the booster of TWT amplifier chain B-284 and presents the corrective actions used in control the mechanisms. 详细地讨论了宽带大功率行波管B-284行波管放大链末级管输出烧毁及驻波变大的失效机理及其纠正措施。