Why does my iPod freeze on the apple logo when a hard drive is in it?

so i have been having this issue with a 30 gb ipod classic 5th gen and it has been driving me up the wall. when the hard drive is in it it freezes on the apple logo and stays that way until the battery dies. so i bought one of those iflash boards and put it in but it still happened. The thing is though, if no hard drive is in it it will boot up fine and get to the sad ipod screen. i can even get it into diagnostics mode, but the minute a hard drive is in it its a brick. I even tried it with a known working drive from my boxed 5th gen and nothing. one thing i did notice though is it never spins up the hards drives if thats helps anyone.