No AC, battery only, works in Dock

chances are the actual power jack in the laptop has gone bad. this is a common issue with lots of laptops and every dell laptop (4) that i have owned http://www.ebay.com/itm/like/281152320878?ul_noapp=true&chn=ps&lpid=82

Not enough power to dock.

There is no manual for the dock. Try with only phone docked, then with only spare battery. If you still have a problem find a Motorola dealer.

If the laptop battery is more than 3 - 4 years old then the battery could be worn out. Rechargeable batteries have a finite number of charge and discharge cycles and will lose their charge capacity over time, i.e. won't charge to 100% and gradually the charge reduces until the battery won't charge up at all. OR The battery shows a 100% charge but when the adapter is disconnected the battery drops off to zero capacity in a very short time. If the battery drops to an unacceptable charge level then the battery needs to be replaced. Rechargeable batteries will fail if stored in a discharged state for long periods.

I had the same issue. I tried opening the dock and could not find anything wrong. It seems the charger was delivering sufficient voltage. So I disconnected power to the charger and reconnected couple of times and it started working again. My charger has a LED light and based on the brightness of the light you can findout if the output voltage is close to 20 volts.

The battery has a dry cell causing this so replace the battery

If it will not power on from battery or AC adapter, Either the power switch is bad - OR the motherboard is shot - OR the LCD is not working. I would suggest taking it to a local PC shop and having it diagnosed, usually this costs about $30 I work for TechSupportPros of Spokane, WA and charge $30 to diagnose computers.

first, check that the battery connection isn't blocked by a sticker or something.
second: try disconnecting the battery and ac and hold the power button for 1 minute. then give the battery and ac another try.

let us know how it goes.

if it still doesn't work, time for a warranty replacement.

You might want to try another AC adapter. If it works, then call up Dell and have replacement on the AC adapter. Otherwise, call up Dell and have them check your motherboard. If the warranty is still active, then can still definitely replace that.

I have found a few things with this model, first if the laptop works on ac power when the battery is out then try pushing the button on the battery itself and see how many lights light up. If they are not green replace the battery it just wore out. Second if you can wiggle the power cord and you see the charge light flash on and off then the solder joints are cracked on the main board and you will have to take the main board out of the case and drill out the 3 rivets on the metal bracket covering the plug and bend it out of the way then there are a small brown and a small black block near the plug resolder the ends of these facing the plug. bend the bracket back into place and epoxy it where it was. put the main board back in the case hook all the stuff back up and now it will charge your battery. If you are not good at this stuff I would not try it yourself. I have fixed 2 c640s this way and it is slow careful work.