[bojan]

14V and 12V are not that different from power point of view (36% more dissipation in the load for 14V).
All inside control electronics (microprocessor, logic and so on), must be powered from internally regulated 5V or 3.3V power supply rail anyway (otherwise they would not work at all).
And those regulators are all rated at 30V input (just have a look at data sheet - for example, MC78L05 or similar).
So, you see, there is a lot of tolerance for input voltage here ..
Of course, if the design of your equipment were bad from the start, then even 12v regulated power supply would damage it sooner or later.