Please remember that working on amplifiers or anything electrical can kill you if you are not careful and well trained. If you don't know what a driver is, I doubt that you are qualified to do any real troubleshooting inside the amp.
I don't know you or what your skill set is, but if you are not up to it, please take the amp in for service.
With all of that being said, Kustom amps are very basic and most of the parts are either available or easily replaceable. They are standard designs that have been used for decades by many manufacturers, and any tech should have no problem in fixing your amp.