Well, your gonna have to open it, provided you have checked the fuse in the plug first.
There should be an internal fuse, your next point would be to check that.
Then get your meter out and check your getting power to power supply, if thats ok coming in, you need to check you have power coming from power supply to board.
Probably power supply.
(If your gonna bin it, I'll have it)
its upto you what you want to do with it but if you cant fix it you can always offer it as spares for sell as the parts are getting expensive nowadays just have a look at some of the sites and see for yourself m8