I own a TomTom Start navigation system. A few weeks ago it suddenly stopped working: It simply would not power on. Yesterday I took it apart to see if there was something I could do to fix it, or harvest some parts if there was nothing I could do. I took it apart but left all components connected to each other, with the exception of the speaker which I had to unplug in order to get the electronics out of the case. Most of the electronics are behind a soldered shield and there where no visible faults on the parts that where freely accessible. So I started by measuring the supply voltage: The battery was still fully charged. At this point I had an idea: What if the TomTom, as many devices do these days, has a small microcontroller that is always powered on and handles stuff like the power-up sequence? What if this microcontroller got stuck? I simply unplugged the battery and plugged it back in. The device booted right away.
So if you have a TomTom and encounter such a problem: don't just throw it away. Instead try unconnecting and reconnecting the battery from the motherboard first. However: It might not be easy to take the device apart and reassemble it if you don't have experience with that kind of stuff. Just remember: You have nothing to loose. Hint: There is a screw hidden behind the hinge for the vacuum cup.
Remains one question: Is this really a bug or planned obsolescence? If done right, it is almost impossible to have such a crucial bug in such a simple microcontroller application. That's why microcontrollers usually have features such as brown-out detection and hardware watchdog timers: so that you can write firmware for them that never hangs, even if there is a critical bug in it or the supply voltage has crazy transients. So either they had extremely bad luck with this particular design, or they designed it to fail approximately one year after the first power-on.
