About 9 years ago I replaced the plate amp for my VTF-3 MK2 with an MK4. A couple of weeks ago I thought my plate amp had gone south so I contacted The good folks here at HSU about purchasing a new amp. After chatting a bit I was told about a quick test to verify if the sub was working by pulling the cable off and touching the end with my finger. Such a simple test but I didn't know. Long story short the sub was fine and my cables were fine. It was a Behringer Feedback Destroyer that was in the circuit and needed a hard reset. I wanted to say thank you for the service and support, some shops would have been happy to sell me a new amp and be done.