K3502 Parking Radar

I’ve completed the above kit and on testing with power, the unit emits a constant buzzing no matter what is in range of the sensors. I’ve re-checked the instalation of components and integrity of joints but cannot find anything that it obviously wrong. Can anyone give me a pointer to where I might have gone wrong.

Thanks in advance,


This is a kit with a lot of IC’s and a lot of solder joints, so check your assembly carefully.
Leave the sensors on the sensorboard.
transmitter is marked with ‘T’ or ‘S’, receiver sometimes marked with ‘R’
‘+’ of sensor has a small plastic ring around the pin.
Distance between sensorboard and main board may not exceed 50-100cm to ensure reliability.