"I have tried Western Digital drives, 2-Green 1-Black, they all went into a constant reboot cycle, so appears they don't work for some reason. These are full size drives and have to be powered externally as appears 630 receiver only outputs 5volts of power and full size drives need 12 volts to spin and 5volts to read/write data. The small 2.5 inch laptop drives only need 5 volts to work as I understand."
I did learn with the 530's that external power on the drive does not work. I think the receiver needs to boot the drive up at a given moment for it to be recognized - or rather the drive can not have power at the moment the receiver is first turned on. Hotplugging the USB connector after boot worked (unplug USB and reconnect) on the 530.
If the 630 is doing this for the same reasons as the 530, you could complicate things and make the full-size drive work on external power by inserting a small relay in the 630 that switches on when power is applied to the hard drive connector - and then use it to switch power to your external drive.