I just had an avalon that was running fine for weeks suddenly stop working

Red/yellow lights are on. The miner starts but it never does any work (hashrate is 0)
Where should I start looking for the problem?
I had one do something similar. It turned out to be a bad USB cable connection inside of the case. The cable that runs from the built-in router to the front of the case makes poor contact with the hub where all of the power and data cables connect. Try pushing the cable to the right or left of the socket. My theory is the vibration of the fans eventually wiggled the cable enough to get it to disconnect. Good luck!