Chosen Solution
iPod classic got a little damp and has been odd ever since. A day after it got wet it would work on our Bose iDock, and plugged in our car. But ut will not power on while plugged into MacBook or plugged into a wall outlet. The moment it is disconnected from iDock or from car it goes dark., and when it is plugged in the apple logo comes up for about 30 seconds before screen fully engages and menus appear. It is probably the battery, though that does not explain why it will not work connected to USB port of MacBook or while plugged into an outlet. Is it the battery or something more dire?
@jhartmire check your dock connector for any corrosion, bend or broken pins. Clean it with some isopropyl alcohol and a few puffs of compressed air. Next replace the battery. It is possible that the limited power from your computers USB port is just not enough for a shorted battery. Your iDock supplies a higher amperage. While you replace the battery you want to make sure that you clean your logicboard with some 90%+ isopropyl alcohol and a soft bush since you may have some corrosion on there as well. iPod Classic Battery Replacement
