I have the HGS 18 and have had amp failures. Simply unscrew the ten or so screws and remove the connecting wiring, put it in a box with some popcorn styrofoam and send it to Velodyne. As I remember the cost was 250.00 for a new replacement. I leave mine on 24/7 instead of the signal sensing on/off feature. They are about 6 years old now. Turn around is fast and Velodyne won't give you the run around. Good company.
