Generally with amplifiers the caps go bad first, and rectifiers take a spike and go bad. At that point its a guessing game if downstream output transistors get destroyed. Not sure if you can repair your original a this time, but if you find a good tech take him both.
If you look around on the internet you can find a schematic and the tuning procedure Velodyne used to tune the amplifier to the driver. You may have to register for a board or two, but those schematics will make you the repair mans best friend. I always have them in hand when I see someone on something outside of warranty.