一台乐声TC201型彩色电视机出现无光栅无伴音故障。该机采用开关电源,当电源及行扫描部分出故障时都会引起上述现象。此时,先采用冷测方法,测量保险丝发现已烧断,换上新保险丝,再测量109伏输出点对地的正反向电阻,发现正反向电阻都很小,为几欧姆,证明109伏对地有短路现象。为了把范围缩 A music TC201-type color TV there is no grating without sound failure. The machine uses switching power supply, when the power supply and the scanning part of the failure will cause the above phenomenon. At this point, the first cold test method, the measured fuse has been found to have been blown, put on a new fuse, and then measure the 109-volt output point of the positive and negative resistance, found positive and negative resistance are very small, a few ohms, that 109 Volt short to ground. In order to shrink the scope