5th gen 30gb iPod overheated, shows sick face, which part to replace?

5th gen 30gb iPod overheated, shows sick face, which part to replace?

I'm not sure which I need to replace, the logic board or the hard disk; the ipod charges fine when plugged into a usb port, but won't show anything on the screen besides the charging logo, the apple logo, or the sick ipod icon.

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