Did you glance inside to make sure the fan was plugged in? If stuff shifted around a lot, or people didn't care during assembly, the fan could be unplugged. These guys turn themselves off if they don't detect a fan spinning after a few seconds.
Might be worth undoing a few screws to check, or just looking inside it with a flashlight through the fan.
Already tried that
Disassembled the unit, took out the boards, verified fan was plugged in, tested with another fan, took out all the hashing boards and tried to get just the main board to just come up. Nada.
Another unit arrived with obvious loose parts and screws fell out when I opened the case. Seems two screws fell off the heatsinks and was causing it to rattle around. Screwed the heatsink back on, reassembled that one particular unit, and it came up just fine.
All in all, though, I have to say I'm pretty darned impressed with these units.