My Raspberry Pi Model B worked fine in one room in my house. I was very excited to trade it in for a newer and faster Raspberry Pi model 2. I just re-used the existing power adapter because it was hard to access. But my new Raspberry Pi, unlike the old unit, was not fine. It crashed from time to time. Just freeze up and need a power cycle to get restarted.
I guess the Raspberry Pi 2 consumed just a little more power than the old model. But not during bootup and normal usage. I eventually and only recently figured out that it was every time I did a sudo apt-get update that it crashed. I guess this gets the CPU literally fired up and consuming more power and putting the thing over the edge, power-wise.
I switched to a kind of adapter used for charging smartphones – i.e., with a 2 amp capacity. Since then it has been fine. This same adapter in fact powers both the Ras Pi 2 and the Raspberry Pi touch display, so it’s much better than the cheapo old adapter.
It took me so long to figure this out because I had a bias that Raspberry Pis are somewhat prone to crash anyway, and sometimes they don’t boot properly, etc. So I figured it was all part of the fragility of the system.
References and related
A first look at the Raspberry Pi 7″ touch display.
Using Raspberry Pis to drive a four-monitor display.