彩电无彩色故障的检修（Maintenance of colour fault in colour TV set）.doc

彩电无彩色故障的检修（Maintenance of colour fault in colour TV set） Recently, many domestic electronic newspapers have published maintenance examples have no color TV fault, when the most talked about narrative maintenance process, no color breakdown appears, check the peripheral parts, no fault, so the first change after the change of crystal, integrated circuit, and color signal related parts be replaced, there is still no color. But at the moment, buy back a few crystal oscillator in turn, and finally have color, so concluded that the quality of the crystal is poor, it seems that only the color of the crystal is the genuine. IMHO, this maintenance method is the maintenance of taboo, is misleading. The replacement of the device in large areas can not only improve the cost of maintenance, but also make the printed circuit board unrecognizable, and the uneven quality of components will also leave hidden dangers to the television. Experienced maintenance personnel are aware of, mainly in the inspection, observation, testing, judgment and analysis based, once judged accurately, the iron wherever it goes, must be the source of failure. In this paper, we will introduce the method of maintenance with color - free fault as an example! No color or color is not normal is a common fault, but not without color will be of a rigid element is damaged, but in most cases is multimeter parameters cannot be detected, so no color is focusing on the fault detection, observation, analysis and experiment. According to the difference of chrominance signal processing circuit and decoding IC structure in color TV, the following observation and judgment of fault point must be carried out without color fault. First of all, to receive TV signals a strong contrast and color, will be adjusted to the maximum, when the color pictures were not clear, no noise, to determine whether the signal strength is too weak because caused no color. Then, with artificial fine keys, the image is adjusted to + and both sid