Usually when stuff like this happens it's generally due to cheap capacitors being used in manufacturing. I never understood this because the cost difference between a crappy capacitor and a decent one is pennies. I have a couple of AV123 15" powered subs for my theater that are notorious for crapping out. There are online tutorials that list parts, where to buy and how to replace them with pictures. If you can somewhat solder you can probably handle fixing yourself so long as a descriptive tutorial such as this exists for your particular device. Do some searching and see what you come up with and if you need help I may be able to. Just fair warning, I'm not a soldering genius and even if you've never soldered you can probably do what I can do with an iron after watching a few YouTube videos.

Also, it's a GREAT time of year to need to replace electronics. Might want to see what is out there and compare pricing and features to see if it's not going to be better just to replace and maybe attempt to sell your unit at a discount. I do this more often than not because you can end up creating even more issues and wasting days of your life away chasing your tail. Hit up SlickDeals.net as they've had the Black Friday & Cyber Monday advertisements posted for about a month now and you can see if there's something out there that would fit the bill.