Update:

Outlaw contacted me about what caused the blown center channel. Here's their response:

"The tech that serviced it found damage at the output consistent with a short across the terminals. In addition to the blown fuses there was a damaged cap, and an open resistor. I should add that it's hard to say whether there was a short or if a component failed but generally speaking a defective part will surface early on, usually in the first month or two of use.

Rather than repairing it he replaced the Center channel with a new module."

The 7700 has performed flawlessly since I've had it back. That's all that matters to me.