Addonics sells a SATA-IDE converter and they nicely include a 4 pin Y power connector. I couldn't get the power connectors to plug in because the pins were bent, and they nicely sent me a replacment. But the replacement had the same problem, and I figured out the reason is actually that the wires in the connector are loose and wiggle easily out of alignment. Here's the male connector: and the female Addonics insists it is completely normal for these power connectors to have loose pins!
Yeah...All mine are like that. You just have to get them in as far as you can and wiggle them in the rest. I've heard IDE-Sata converters promote corrupt data and are piles of junk.