许多学校、单位的扩音机均是老式的电子管扩音机,这些扩音机安装有低压开关和高压开关,正确的开机顺序应是:先开低压,待灯丝预热5-10分钟后,再开启高压,关机顺序则相反。然而,由于一些单位的管理人员忽视或根本不懂这一操作规程,在灯丝尚未充分预热的情况下开启了高压,甚至干脆不管顺序胡乱开启,极易造成电子管阴极中毒使电子管过早衰老 Many schools, the unit’s amplifiers are old tube amplifiers, these amplifiers installed low-voltage switch and high-voltage switch, the correct boot sequence should be: first open the low pressure until the filament warm-up 5-10 minutes, and then open the high-pressure shutdown order The opposite. However, due to the ignorance or lack of understanding of this procedure by managers of some units, the high voltage was turned on even when the filaments were not fully warmed up, and even premature aging of the tube caused by cathodic poisoning of the tube was easily caused