论文部分内容阅读
故障现象:满屏水波状波纹晃动。检修:拔去天线短路天线输入孔,故障存在,证明故障在机内,按常规判别故障应在信号通道上。分别断开高放输出、中放输出、亮度输出,故障依旧。肯定故障出在视放板上,测量视放级电压发现180V电压为150V偏低,断开180V电源输出端,测量180V电源仍为150V,证明180V电源有问题。该机180V由开关电源提供,焊下180V电源整流滤波电容C_(350)、C_(351)均已开路,更换这两个电容(均为4.7μF/250V电解电容)故障排除。
Symptoms: full screen wave ripples shaking. Overhaul: unplug the antenna short-circuit antenna input hole, the fault exists to prove the fault in the machine, according to the conventional fault should be in the signal channel. Disconnect the high-output, respectively, put the output, brightness output, the fault still. Positive fault is placed on the board, measuring the playback voltage level 180V found low voltage of 180V, disconnect the 180V power output, measuring 180V power is still 150V, 180V power supply that there is a problem. The machine 180V by the switching power supply, welding 180V power supply rectifier filter capacitor C_ (350), C_ (351) have been open, replace these two capacitors (both 4.7μF / 250V electrolytic capacitor) troubleshooting.