Disk I installed: WD250BEVE. ($89.99 in Microcenter as of today - brand new offer just started)
Disk that needed exchanging: WD120BEVE (was $59.99 in Microcenter the other day).

Both run at 550mA max current draw, 5V. And the power supply I have is rated up to 1A, 12V. Beyond that I'm done double guessing what the heck was wrong with that other "OEM" disk I bought.

Jon.