What causes their sudden death?
In one word: heat. Contrary to what Apple suggests by their magical “affected serial numbers list”, the serial numbers in the Time Capsule Memorial Register show that the problem that causes the Time Capsules to prematurely die is not limited to certain production batches. Experts on the subject, like LaPastenague, have confirmed that it is the flawed thermal design that causes Time Capsules to stop functioning, not the quality of the components used. All components, including the power supply, are squeezed together in a very small package with hardly any ventilation to cool them down (in fact, that rubber foot works as an insulator). There is a fan inside the Time Capsule, but it is totally inadequate (it will start only at extremely high temperatures, and will only circulate hot air). The first components that die from the prolongued exposure to high temperature are the capacitors in the power supply unit.
Will my replacement Time Capsule last?
Well, only time will tell… As you can read in the preceding item, the heat buildup is what kills the Time Capsules. The newer Time Capsule models have almost the exact same design, but they do feature a “green” hard drive that produces significantly less heat. This hard disk may be the saviour of newer Time Capsules (in fact, at the Time Capsule Memorial Register, we exchanged the hard disk of our refurbished replacement Time Capsule for such a disk), but it’s too early to tell. Unfortunately, replacement Time Capsules are not likely to feature these “green” hard drives.