维修格力外机主板一例教训，及疑问请教

 Then there is no power, the measured, 3.3v voltage has reached 5v, and found that the replacement, 3.3v no, disconnect the load 3.3v recovery and found that the master chip and breakdown, in the dead horse when the live horse doctor, another grid in the motherboard measured a main chip, the cost of the effort, after a good change , The board lights flash up, because no internal board, only to this step,
接一台格力报E6，查外机主板无300v电，发现桥堆损坏，更换有电，15v，5v输出，仍无灯显，后测，3.3v电压已达到5v了，更换后发现发现，3.3v无，断开负载3.3v恢复，发现主控芯片又击穿，本着死马当活马医，在另一个格力主板测一块主芯片，费了九牛二虎之力，换好后，主板灯闪起来了，因无内机板，只能到这步，


请教，主板号不一样，主芯片能正常工作不，但红灯有闪，有一定规律，


在维修电源时，是否要断开，3.3v供电，防止电压过高烧坏主芯片，赐教，

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格力变频外机板有些通用，有些不通用。凉之静和U酷通。