Behringer mixers work only for small live performances. I'd never use them for recording. They're too noisy. As to repair, what others have said is the best advice, They are cheap and will cost more than they are worth to repair unless you plan on doing it yourself. If you have those kind of skills, once you are in there you could maybe make some other mods to fix the manufacturer flaws (like all of the cross noise). I have two little Euroracks that I use for small clubs with two other musicians to plug into a 100 watt amp. For those applications, these little mixers work fine. For more serious and larger gigs, I use a 16 track Yamaha mixer through a 1300 watt crown amp and two large Cerwin Vega cabs. The reason I need to use the Behringer mixers is to mic three instruments (two that are miced with mini condensers) and the little Behringer will give me phantom power and saves me from lugging a large rack into a small club, restaurant or library. The sound is adequate, but tinny and harsh.
