faulty target lrc100

My target lrc100 has been installed into my new car about 4 weeks. when i switch it on, it doesnt always make the two beeps that you should get. At first i thought it was a bad connection so i cheched all the connections. Then i noticed the wire from the back of the diode had partialy melted on the radiator. I have now cut that wire down and reconnected it without the melted bit. Still only working inermittently.
is the diode on its way out i wonder?

LRC-100 = Lidatek LE-20. Mine still works on the laser, but no sound anymore.