故障现象 无光栅、伴音只有很小噪杂声.分析检修 这种无光栅故障一般发生在行扫描电路.开机后观察到灯丝不亮.用电压档测量开关稳压电源的114V和24V输出电压,均正常.初步证明开关稳压电源工作正常,故障肯定在行扫描电路.应重点检查行扫描电路的行振荡、行推动、行输出各级的工作状态.用万用表电压档测行输出管Q_(404)的集 No grating phenomenon, only a small noise noise analysis and maintenance of this non-grating failure generally occurs in the line scan circuit. Failed to observe the boot after the power switch voltage measurement using voltage 114V and 24V output voltage, Are normal. Preliminary proof of the switching power supply is working properly, the fault must be in the line scan circuit. Should focus on line scan circuit row oscillation, line promotion, line output at all levels of the work state. 404)