My 30gb classic ipod has a sad face and does not charge

my ipod is on only bat not working anything

Re-boot

could be bad charger or time to replace the battery. lots of places sell new ipod batteries.
does it work if you leave it plugged into your computer for a few hours? if it does not then its a bad abttery.

hard drive

sadly it's dead...go to apple.com and buy a refurbished unit or ebay.

Listen to the iPod - if you don't hear the hard drive spin properly and evently when it starts up you may have a hard drive issue. If it doesn't spin at all, you may have a logic board issue? Here is a ipod repair guide on how to dismantle and iPod classic.

This is generally caused by a hardware failure. If it's under warranty, send it back to Apple. Otherwise, you need to start looking at replacing the hardware. If the screen shows a sad face, then you can assume the screen and battery are probably OK. So, the problem is probably with the hard drive or the logic board.

Don't just change the hard drive,Change the motorboard as well.Different generation ipods use different boards and the hard drive from one won't always just plug in and work.

Unhappy face
http://www.zolved.com/synapse/view_content/19230
I have been told this is because the speaker wires are pushing against the laser motors. How can I fix this?

To reset an iPod with a Click Wheel, including:

• iPod nano (3rd generation)
• iPod classic
• iPod (5th generation)
• iPod nano (2nd generation)
• iPod nano
• iPod with color display (iPod photo)
• iPod (Click Wheel)
• iPod mini
• iPod mini (2nd generation)

1. Toggle the Hold switch on and off. (Slide it to Hold, then turn it off again.)
   
2. Press and hold the Menu and Center (Select) buttons simultaneously until the Apple logo appears, about 6 to 8 seconds. You may need to repeat this step.

Tip: If you are having difficulty resetting your iPod, set it on a flat surface. Make sure the finger pressing the Select button is not touching any part of the click wheel. Also make sure that you are pressing the Menu button toward the outside of the click wheel, and not near the center.
If the above steps did not work, try connecting iPod to a power adapter and plug the power adapter into an electrical outlet, or connect iPod to your computer. Make sure the computer is turned on and isn't set to go to sleep.