There is no reset button, if you've confirmed that you have a good ground and sufficient voltage on the B+ and remote terminals, the ampifier is in need of repair.

If you're interested in troubleshooting/repairing it yourself, read through the following page to familiarize yourself with the inner workings of an amplifier.

Basic Amplifier Repair Tutorial

A common problem on these amps is broken connections on the remote turn-on connector lug. If it's loose in the board, that would be the first thing you'd need to repair.

Let me know if you have any other questions.