请PI工程师帮忙看一下整流管波形!(有图)

TNY267电源,7.5V300ma,18V200ma,当18V输出到120ma左右时整流管波形有很多毛刺出现(如下图),不是连续出现,输出电流越大毛刺越多,空载时没有,整流管用的是UF4003,变压器参数如下:初级100T,18V 17T,7.5V 7T,请各位帮忙分析一下什么地方有问题?谢谢!
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整流管带载时波形
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整流管空载时波形
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空载时VDS波形
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带载时VDS波形