故障现象:一台东芝2918K型彩电经常不定时地出现爬行现象,故障的持续时间长短无规律,有时几秒钟,有时则可延续一段时间。分析检修:爬行现象是PAL制彩电特有的故障,当该故障出现时,可在屏幕上看到一道上下移动的横色带。由此可肯定故障出在梳状滤波器及其有关电路。该机由于故障出现不稳定,且又没有明显规律,所以给检修带来一定的难度。据故障现象分析,估计是由于某元器件或电路焊点有接触不良故障所致,该机的 Symptoms: A Toshiba 2918K color TV often appear from time to time crawling phenomenon, the duration of the fault irregular, sometimes a few seconds, and sometimes can be extended for some time. Analysis and maintenance: Crawling phenomenon is PAL-specific color TV failure, when the failure occurs, you can see a screen up and down the movement of a horizontal ribbon. This can be sure that the fault lies in the comb filter and its related circuits. The aircraft due to instability instability, and there is no obvious law, so maintenance to bring some degree of difficulty. According to the phenomenon of failure, it is estimated that due to a bad contact with some components or circuit solder joints due to the aircraft’s