Flash has stopped working, is it fixable?

chris, you did not mention if you get an error code. Anyhow, you can of first try to reset your camera by first turning of your camera. Remove the battery or external power supply. Press and hold the power button for 30 seconds. Install the battery or external power supply. If that does not work, and you are sure your flash is on, you may have to replace the flash assembly. The instructions for that are here. You can also download the service manual for your camera from here. The part number is 1-479-663-31 and it is available at places like this. On the assembly, you will find a large capacitor, check that one for bulging and leakage. It is possible that all you need to do is to replace is that. Might cost you a few $$ but cheaper than the assembly. Hope this helps and good luck. Let us know how it turns out.