Well I guess it might help if you told us the problem and what you have done so far to try to fix it and what makes you think it is the Phantom power that is bad...?
If you have never done any electronics repairs before then it might be a bit out of your league depending on what the problem is...If you are lucky you will open it up and see a burnt out component that you can just replace but things are rarely that simple and without a schematic of the unit it will be even more difficult to diagnose...