The old time capsules have a power problem, there are loads of them dying after 18months.
Good news is you can attach it's warranty to any computer you have apple care and they will fix it under warranty as long it was purchased within one year of the said computer.
Unless it's been used with a pc.
Of course i had bought mine about 15 months after my laptop so it wasn't covered...
but they gave me a warranty exception code so they will replace the whole thing...
unfortunately i had modded it with a big antenna so that could jeopardise apple's good will...
the saga continues!