Unit probably 4 years old. Straight DFI from a Yamaha amp. Working great then it suddenly stopped working tonight. Remote only elicits an occasional flash from the front blue light but is otherwise ineffective. Blue light also not active except for the occasional flash when repeatedly pressing the LED remote button. Power light is blinking green. Volume up and down with the buttons on the back ineffective. Battery in remote works as I tried it in another device. Yamaha amp also working fine. I did unplug the sub for 15 minutes but that did not help. Help?