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强哥拿给我一块板,我一看板上缺了好多元件。心里就荒了!我说这般还能修吗?他说:能,把3/5V修出来就可以了。然后我就开始修。。。。。。。。。 第一步:测公共点没有短路。 第二步:插电,公共点正常。 第三步:测3/5V电感后端,示波器没反应,说明电压没出来。如图:file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image002.jpg 第四步:查上管D极有19V,G极没输出。就查芯片的工作条件:供电正常、3 / 5V线性开启正常。3 / 5V线性输出正常,抓到波形如下: 线性5V测量点: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image004.jpg 线性5V的波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image006.jpg 线性3V测量点:file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image008.jpg
线性3V波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image010.jpg
第五步:查PWM的开启。发现没有电压。看芯片的维修手册 file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image012.jpg查点位图,EN1和EN2file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image014.jpg 查它周边的元件和电压来源。
发现电容和电阻的位置装反了。如图: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image016.jpg 有波形,但因为被换成电容,电压file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image018.jpg过不去。 file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image020.jpg
换好后: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image022.jpg 换好后的测量:
5V电感后端: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image024.jpg 5V电感后端波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image026.jpg
3V电感后端: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image028.jpg
3V电感后端波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image030.jpg
3V电感前端: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image032.jpg
3V电感前端波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image034.jpg
5V电感前端: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image036.jpg
5V电感前端波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image038.jpg
3V上管G极: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image040.jpg
3V上管G极波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image042.jpg
5V上管G极: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image044.jpg
5V上管G极波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image046.jpg
5V上下管G极: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image048.jpg
5V上下管G极波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image050.jpg
拆掉3V上管,测5V电感后端: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image052.jpg
拆掉3V上管,测5V电感后端波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image054.jpg
拆掉3V上管,测5V上管G极: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image056.jpg
拆掉3V上管,测5V上管G极波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image058.jpg
不装两路上管,3V上管G极: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image060.jpg
不装两路上管,3V上管G极波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image062.jpg
不装两路上管,5V上管G极: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image064.jpg
不装两路上管,5V上管G极波形: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image066.jpg
双通道同时测量EN信号与电感后端: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image068.jpg
双通道同时测量EN信号与电感后端波形对比: file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image070.jpg
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