海信液晶电视LED55EC280JD不开机主板5277维修刷机
本人修板纯属小白，不对之处请高手指正！同行一台海信液晶电视机LED55EC280JD(BOM2)不开机，只拿主板7.820.5277就转手到我这，放置好久了。接上主板12V供电，测量5V、3.3V、1.5V、1.2V均正常，连上编程器无打印，试写引导mboot提示“Read EMMC ID Failed!”，意思是读EMMC失败！https://p3-sign.toutiaoimg.com/pgc-image/854f840e2d0243adbdfa49b269f1e3ce~tplv-tt-large.image?x-expires=1974464717&x-signature=PYMdPdFkWdqM6j44aXrmEeeao1E%3D
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试按“ESC”键开机也不能进控制台，咨询同行师傅说可能是emmc坏。此机EMMC是2G海力士2100。先后分别换三片EMMC换东芝THGBM5G5A1，三星4G故障一样。不可能换的都是坏的吧！因为这主芯片之前是换过的，所以又怀疑主控芯片MT5505AKDI没焊好，又重新拆下植锡焊上涛声仍旧，此时没有思绪了。
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于是心静下来慢慢思索着。不识别EMMC要么是主芯片坏了，要么是主芯片与EMMC通讯不畅。主芯片拆装已好多遍了坏得可能性较大，但是手中也没有这MT5505AKDI芯片。既然我与这主板较上劲了就不服输！还是先查通讯吧，用放大镜仔细慢慢查过孔终于有了不通的孔，心里有点暗喜。
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连好过孔通电仍写不进引导，真是白高兴一场。心想既然能发现过孔故障，还有多路的通讯为何不测量它呢？之前光测量过孔时间就花很长时间啊，眼都看花了。功夫不负有心人，终于测量R536、R538阻值变值（正常值是0欧姆）。再次焊上主芯片MT5505AKDI及EMMC芯片连机可以写引导，也可以进控制台了，马上升主程序打印完全正常了。
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这次主芯片MT5505AKDI是从旧板上拆下的，维修过程中拆装多遍仍完好无损，不知是我运气佳还是质量过硬就不追究了。（作者：胡家进www.jdwx.info）
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