Weltronics AMC 2445 2 / 4 Channel Power Amplifier; 3 Channels Working AS-IS

This amplifier was used in a very high-end, whole-home custom install. Is was inside a rack... very little cosmetic wear showing. It is designed to be used as a either a 2 channel or 4 channel amplifier. However, one of the channels is not working... it just emits a steady hum. We've marked that input with an "x". The others work fine. This would actually work great in a home theater configuration. It sounds great.