1.当lock loss 灯不正常时。
turn on the TPU , and check the lock loss light, after 45 seconds the lock loss light not go off or flickering, there are some problems
first, tofish fuse failure
second, cable problem
third, check transmitters, start sonarpro set a rang of 100 meters, see the transmit wave form, if there is a problem, it will show up a very weak transmit wave form or none at all.
2.检查拖鱼各组件电压
拖鱼各组件连接：
其中multiplexer board的功能是接收200VDC并转换出15VDC和5VDC分别给对应的board.
接收板的各个单元连接处的电压量测方法：
检查FET的电阻