Generally, if the amplifier smokes, the power supply FETs have failed.
Many times, the output transistors fail and that causes the power supply FETs to fail.
Audiobahn won't release schematics. The amplifiers are relatively simple and a schematic isn't generally required.
If you know how to check the transistors, check them to determine the severity of the damage. If you don't know how to check them, read through the following page following all links provided. Basic Amplifier Repair
Let me know if you have any other questions.