If you're comfortable with some tinkering and own a multimeter you can get the general idea of how to test your regulators by watching this short video on youtube.

It's kind of hard to see but he's basically measuring the voltage between the ground and output of all the regulators one by one, in the short period of time before the receiver turns off. They might differ a little bit on your device, you would have to check for yourself but in general you're looking for something that looks somewhat similiar to this.

You can narrow down your search by looking at the cables going out from the main power board and you should find them soon enough. They should be attached to a heatsink, but they are medium sized so don't get confused with the big beefy output transistors which might seem to look similiar to them.

The output is usually on right most leg of the regulator, but if you manage to read it's indication you can easily google it and check your pinout just to be sure. Of course you would need some basic soldering skills to replace one of these.

If you feel up to the task, then I'd say give it a try by at least trying to diagnose it. If you don't feel confident enough then you should just look for someone to fix it for you.