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例1 开机后满屏红光栅,伴音正常。分析检修:根据故障现象,检修重点放在彩色显像管和视频输出电路。打开电视后盖,拨下显像管管座,用万用表R×1Ω档测显像管R阴极⑦脚与第一栅极G_1⑥脚、灯丝④脚间的电阻,均为∞,说明显像管无问题。装上管座,开机测视放管Q_(851)(2SC3417)的集电极电压为50V,远低于正常值122V,而基极、发射极电压分别为7.3V、7.7V,正常。视放电压180V也正常。焊下Q_(851)检测发现c、e极间严重漏电。用2SC2688更
Example 1 full screen after switching on the red grating, sound normal. Analysis and Maintenance: According to the fault phenomenon, overhaul focus on color CRT and video output circuit. Turn on the TV back cover, dial down the CRT seat, with a multimeter R × 1Ω file test picture tube R cathode ⑦ foot and the first grid G_1⑥ foot, filament ④ foot resistance, are ∞, indicating no problem with the picture tube. Installed on the tube base, boot monitor discharge tube Q_ (851) (2SC3417) the collector voltage is 50V, well below the normal value of 122V, while the base and emitter voltages were 7.3V, 7.7V, normal. As the voltage 180V is also normal. Welding Q_ (851) test found that c, e very serious leakage between poles. With 2SC2688 more