Just got to the bottom of why my AD1 wouldn't show up on any system I connected it to, the PCB mounted Micro USB connector has completely lifted off the board and pulled up 4 of the 5 pads with it. Really disappointed as this unit has probably had less than 100 connect/disconnect cycles. There was not enough solder on the tabs that hold it on the PCB, it's come clean out leaving slots in the solder pads.
I'm not sure how I'm going to repair it, I might re-house it in a Hammond case with a captive USB cable, BNC panel mounts for the analog inputs and wavegen and banana posts for the power supply (I've never used the digital I/O).
I'd Recommend anyone with an out of warranty AD1 open it up and check the MicroUSB connector and reflow the mechanical mounting tabs before it goes the same way.