故障现象为GW—600C彩显关机后出现亮点。 从现象上看,肯定为消亮点电路元件故障。但是由于没有电路图,给检修增加了难度。借到一份GW—500型电路图(见下图)当作参考。从原理分析得知,当开机工作时,Q_(310)处于饱和状态,为显像管G_1(一栅)提供—27V～—48V的亮度调节通路。当关机时,Q_(310)B、E结断电,管子处于截止状态。而D_(404)从FBT5脚取得 Fault phenomenon is GW-600C bright color after the shutdown appears bright. From the phenomenon point of view, certainly for the bright spot circuit components failure. However, because there is no circuit diagram, to repair more difficult. Take a GW-500 type circuit diagram (see below) as a reference. From the principle analysis, when the power is turned on, Q_ (310) is saturated, providing a luminance adjustment path of -27V ~ -48V for the picture tube G_1 (one gate). When shut down, Q_ (310) B, E junction power, the tube is in the off state. While D_ (404) is taken from FBT5 pin