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故障现象:刚开机时图像模糊,需10min(分钟)后才清晰,用户未予理会,到后来机器需预热半个小时荧光屏才亮。在一次机器预热的过程中,机内突然发出“吱吱”声,并伴有焦煳味,关机后再开机,机器再无动静。故障检修:由故障现象怀疑“管座”已受潮变质。开盖观察,发现“管座”聚焦盒内有铜绿渗出,聚焦引线已被蚀断,电路板和显像管脚也沾满绿色氧化物,拆之并清洁干净绿色污物,更换新“管座”后通电试机,面板指示灯点亮,但整机无动静,“二次开机”也无效。观察主板电路,又发现电阻R325、R309、R314己烧焦,测量之,均已开路,对照电路图1,将R309(8.2kΩ)、R325(22kΩ)换新,而对于R314在随机图纸上未能找到,
Symptoms: just boot the image fuzzy, take 10min (minutes) after clear, the user has not ignored, and then the machine need to warm up for half an hour before the screen bright. In a machine preheating process, the machine suddenly issued a “creak” sound, accompanied by coke smell, turn off and then boot, the machine no movement. Troubleshooting: Suspected by the phenomenon of “socket” has damp deterioration. Open the lid and found that the “tube” focusing box with exudate patina, focus lead has been etched off, the circuit board and the imaging pin is also covered with green oxide, remove and clean clean dirt, replace the new “tube After the power test machine, panel indicator light, but the whole machine no movement, ”the second boot" is invalid. Observed the motherboard circuit, and found that resistors R325, R309, R314 have been burnt, the measurement, have been open, the control circuit Figure 1, the R309 (8.2kΩ), R325 (22kΩ) for the new, turn up,