iPod has a new hard drive and still getting sad iPod icon.

I'm a bit out of ideas. I have a ipod 30gb 5.5gen video. I bought it off ebay in hopes to repair it. It powered on to a sad icon. After a bit of reseating, resetting, and cable checking etc. I gave up and bought a new hard drive and connector for it. After install of the new hard drive it fired up ok but I noticed the hold switch not working. So I opened it back up and made sure it was in ok. Closing it back up it now shows the sad icon again. I noticed that it takes 3 resets (menu + select) for it to fire up properly or even go into disk mode. I reformated the HD and reinstalled the software. I also got it to play music but it still randomly freezes. Is the connector to the HD still the problem? Perhaps I didn't set it right? I made 100% sure the HDs were the same and they are. Is there more issues I'm unaware of that causes the sad icon face like the broken hold button that I'll eventually replace? Some times it likes to cycle low battery and sad icon but battery charges up fine and holds a charge for a day. At least i think it does. As well as a side note Itunes detects it just fine.

EDITED NOTE: While testing I noticed it freezes exactly every two songs on clockwork and the battery fluxes from 50% full to a sliver of red. Perhaps I'll change the battery while I'm at it.