The detector is deaf as a post, it will pick up the side of a car and not much else.
First check the n channel fet near the coil connections, these fail due to metal migration in the semiconductor layers.
Near the lm 394 ic on the input there is a 68 pf capacitor that is leaky, that is that it still measures like a capacitor but it starts becoming resistive, i have found this capacitor to fail on countless sd2000 detectors. It s located near he 4093 ic that controls the gate timing of the receive fets, it is used as a timing delay to give a small delay before turning on the fets after the end of the transmit pulse.
