徒弟:请师傅分析检修LA7680单片机(A3机芯)无彩色故障好吗? 师傅:好!由于LA7680为日本三洋公司出的性能优良、集成度高的大规模集成电路,因此外围元件很少,故障率较低。检修无彩色故障时,应重点检查色信号通道和副载波振荡电路外围元件,特别是电容器。现以金星C5438型54cm彩电为例,多发故障部位介绍如下: (1)LA7680(16)脚外接的4.43 MHz晶振性能不良或虚焊,造成4.43MHz副载波振荡器停振,使内部的 Master: Good! As the LA7680 for the Japanese Sanyo’s excellent performance, high integration of large scale integrated circuits, so few external components, fault Lower rate. Overhaul without color failure, should focus on checking the color signal channels and subcarrier oscillation circuit peripheral components, especially capacitors. Venus C5438 54cm color TV is now an example of multiple fault locations are described as follows: (1) LA4380 (16) pin external 4.43 MHz crystal performance poor or Weld, causing the 4.43MHz subcarrier oscillator to stop the vibration so that the internal