PICKIT3收发器死亡

嗨，我已经在自己的板上使用了我的PICtiT3好几个月了，然后有一天它无法检测设备ID 0x00，尝试另一个PIDIT3，也无法检测ID，试试另一个板，这也行不通。因此，在引脚范围内，MCLR只在5和4V之间切换，另一个CLK和DAT引脚不切换到0V，因此替换了TrimeCIES，并且切换OK，但是仍然看不到设备，替换PIC33 FJ256MC710A，并且再次工作正常。因为我把它们都用在其他的板上了，很好，但是插入了我的可疑板，不能再读取设备ID，不得不替换U8和U9，OK，但是担心这会继续发生，有什么想法能引起这个吗？谢谢！



      以下为原文

    Hi,

I've been using my PICKIT3 on my own board for months without issue, then one day it cannot detect device id 0x00, try another PICKIT3 and that too cannot detect ID, try another board and that wont work either. So scoped the pins and saw that on one the MCLR was only switching between 5 and 4V and the other the CLK & DAT pins wheren't switching down to 0v, so replaced the transcievers and was switching ok, but couldn't see device still, replace the PIC33FJ256MC710A and working ok again. Since I've used both of them on other boards, just fine, but plugged into my suspect board and couldn't read device ID again, had to replace U8 & U9, ok again, but fear this is going to keep on happening, any ideas what could be causing this please?
Thanks!